Underwrite a Texas Duplex

Underwrite a fictional Texas duplex for live-in costs and rental cash flow.

Introduction

30 Second Summary

A home with rent coming in can look affordable at first glance. The full picture changes once financing, repairs, and empty units enter the numbers.

In this project, you will complete a fictional Texas duplex underwriting and decide whether a house hack meets your limits from purchase through exit. You will use Google Sheets, Google Docs, and your existing AI chat client to keep the calculations, sourced facts, and decisions in one deal file.

What You'll Build

At minute 60, you can show whether the duplex beats your apartment while you live there and whether it supports itself after you move out.

By the end of this project, you'll have:

A buy box and walk-away point you can use to screen every simulated option before choosing one duplex.
A working underwriting spreadsheet that shows the full monthly payment, live-in housing cost, and move-out cash flow from sourced simulation facts.
A decision log you can use to defend your funding choice, fictional negotiation, closing choice, first-year response, final score, and 60-word lesson.
Secret Mission: Complete the exit audit and score your original two-part prediction without changing it after seeing the outcomes.

Are there any prerequisites?

You need the four supplied blocks headed Your Position, Game Master Card, Spreadsheet Layout Block, and Reality Block. The supplied Check section stays closed until Phase 6.

Before We Start

Before any hands-on work, commit to a fictional study simulation that treats owner occupancy truthfully without providing legal, tax, lending, or investment advice. Every real-world action stays undone in an outbox, including any loan quote, application, offer, contract, signature, inspection, appraisal, tenant action, transfer, payment, or professional contact.

Set Your Buy Box

A written buy box gives every property the same test. A walk-away point defines when the answer is no.

This step converts only the supplied Your Position block into fixed decision rules. Those rules prevent later property summaries from moving your limits.

In this step, get ready to:

Prepare your browser workspace for underwriting.
Write a four-part buy box from Your Position.
Set one walk-away point plus one unchanged two-part prediction.

Prepare your workspace

Google Sheets holds the underwriting numbers you calculate later. Google Docs holds the decision rules that guide those calculations.

The decision log also contains an Outbox for possible real-world follow-ups. Your Position is the only supplied block used in this step.

In your browser, use Google Sheets to create one blank spreadsheet.
Title the workbook Texas Duplex House Hack Underwriting.

You should see the project title at the top of a blank workbook.

In another browser tab, use Google Docs to create one blank document.
Title the document Texas Duplex House Hack Decision Log.

You should now have one titled workbook plus one titled decision log.

Add an Outbox heading at the top of the decision log.
Read only the supplied block headed Your Position.
Leave every protected block closed.

Keep the simulation sealed

Protected content includes the Game Master Card, Spreadsheet Layout Block, Reality Block, plus the Check section. Keeping them closed protects your original judgment from hindsight.

Write your buy box

A buy box turns your starting position into limits you can test. Its four fields stop a persuasive property summary from moving the goalposts.

What belongs in your buy box?

Property type states what kind of home qualifies.
Location states where the property must be.
Maximum price sets the most you can pay.
Maximum live-in monthly cost sets the highest acceptable housing cost while you occupy one unit.

Switch back to the decision log from earlier.
Add a Buy Box heading below the Outbox section.
Review every fact in Your Position before setting a limit.
Write one buy-box statement that covers all four fields using only those facts.

You should see one decision rule covering property type, location, maximum price, plus maximum live-in monthly cost.

Why use an Outbox?

An Outbox separates possible future research from the fictional simulation. It preserves useful questions without turning them into real transactions or professional contacts.

Add every identified possible real-world follow-up to the Outbox.
Label each item Public research only. No live deal. No action performed.
Leave each Outbox item undone during the project.

Your decision log now separates current fictional decisions from future public research.

Set your walk-away point and prediction

A testable walk-away point turns a weak spreadsheet result or simulated event into a clear rejection. It keeps the deal from surviving through wishful thinking.

Your two-part prediction records the expected live-in result plus move-out cash flow before any outcomes are known. Keeping that prediction unchanged makes the final audit honest.

Add a Walk-Away Point heading below your buy box.
Write one specific rule that a spreadsheet result or simulated event can clearly trigger.

You should be able to use the rule later without changing its meaning.

Add a Prediction heading below the walk-away point.
Write one line predicting whether living in one unit costs less than your apartment rent.
Complete the same line with a prediction about whether rent from both units covers all monthly property costs after move-out.
Leave the two-part prediction unchanged for the rest of the simulation.

Before you inspect both files, do you expect every decision rule to produce a clear pass or fail later?

Confirm Texas Duplex House Hack Underwriting is visible on the blank workbook.
Confirm the buy box states a property type, location, maximum price, plus maximum live-in monthly cost.
Confirm the walk-away point can be tested against a spreadsheet result or simulated event.
Confirm the unchanged prediction covers the live-in result plus the move-out result.
Confirm every possible real-world follow-up sits in the Outbox with its public-research status.
Confirm the protected simulation blocks plus the Check section remain closed.

At minute 4, your Google Doc should show a complete buy box, one testable walk-away point, one unchanged two-part prediction, plus an Outbox. Your Google Sheet should remain blank except for its project title.

Strong start. You now have fixed rules for judging every simulated duplex.

Your limits are fixed before any property appears. Next, you will use them to screen simulated duplexes without letting the AI choose for you.

Screen the Simulated Duplexes

Your buy box sets the purchase limits in your Google Docs decision log. Your walk-away point gives you a boundary for screening the simulated duplexes.

Property summaries can sound persuasive while leaving decision-critical facts unanswered. You will apply your written rules to every option while preserving each missing fact as unknown.

In this step, get ready to:

Start the controlled fictional simulation in your existing AI chat client.
Screen every option using your buy box.
Select one duplex to advance with a written justification.

Start the controlled simulation

Your existing AI chat client becomes the game master for a controlled fictional deal. The supplied Game Master Card controls what each simulated character can reveal.

Start a new conversation using the new-conversation control in your existing AI chat client.
Copy the complete supplied Game Master Card without reading its protected details.
Paste the complete Game Master Card into the conversation's message field.
Submit the Game Master Card to establish the fictional simulation.

Before you request properties, do you think every option will include enough information to test every buy-box limit?

Ask the simulated agent to release duplex options.

You will see the simulated agent release multiple duplex options. The summaries leave some buy-box facts unanswered.

Keep the roles separate

The simulated agent releases the property facts available at this point in the exercise.

You perform every comparison. You also make the selection yourself.

Screen every option

A screening record makes each decision traceable to the limits you wrote before seeing the properties. Missing information stays visible as a question for later fact checking.

Switch back to the decision log from earlier in Google Docs.
Add a screening section immediately below your unchanged prediction.
Create one screening entry for every option released by the simulated agent.
Record only the facts released for each option.
Mark every missing fact as unknown.
Test each option against every limit in your buy box.
Write one pass or fail reason for each limit.
Move any possible real-world follow-up to the Outbox as public research with no live deal.

Why unknown stays unknown

An unknown preserves the difference between a released fact and a gap in the record.

An estimate would hide the question that deeper fact checking must answer.

Keep the Google Sheets workbook from earlier blank during this screening phase.

You should see one screening entry for each simulated option. Every buy-box limit has a pass or fail reason based only on released facts.

Select one duplex

Advancing one property creates a clear case for deeper analysis. Your written rationale keeps the choice tied to the original rules.

Review every completed screening entry.
Apply your original walk-away point to each option.
Record the walk-away result for any option that triggers the rule.
Select exactly one simulated duplex to advance using only the released facts.
Follow only the supplied fictional continuation if the selected option triggers your walk-away point.
Write why the selected duplex advances.
List the buy-box tests the selected duplex passes.
List every unanswered question that could still end the fictional deal.

Protect your original judgment

Your original buy box, walk-away point, and prediction form the baseline for the final audit. Keeping them unchanged makes later scoring honest.

Keep your original buy box, walk-away point, and two-part prediction unchanged.

Before you make the final check, do you expect every option to have a defensible pass or fail result from released facts alone?

At minute 12, review every screening entry in the decision log.
Confirm that every simulated option has a pass or fail reason.
Confirm that exactly one simulated duplex is selected to advance.
Confirm that the selected duplex has a written justification.
Confirm that the selected duplex lists its passed buy-box tests.
Confirm that the selected duplex lists its unresolved questions.
Confirm that every missing fact remains marked as unknown.
Confirm that your original decision rules remain unchanged.

Keep the analysis inputs sealed

The deeper underwriting phase uses the remaining protected material in its planned order. Keeping it closed now protects the simulation's evidence trail.

Confirm that the Google Sheets workbook remains blank.
Confirm that the Spreadsheet Layout Block, Reality Block, and Check section remain unopened.

You should see a complete screening record for every option. You should also see one selected duplex with released facts, passed tests, unanswered questions, and a written rationale.

Strong work. Your selection now traces directly to the rules you wrote before seeing any property.

Your simulated duplex is ready for deeper analysis. Next, you will build the underwriting record from sourced facts.

Build the Underwriting Model

Your screening record has one duplex worth advancing. The unresolved questions now determine whether its numbers support that choice.

This step turns released facts into a sourced underwriting model in Google Sheets. The finished comparison tests your unchanged live-in prediction without opening the Reality Block or Check section.

In this step, get ready to:

Reproduce the supplied spreadsheet layout exactly.
Build a sourced fact log from every simulated person.
Calculate the live-in comparison using PITI, mortgage insurance, required monthly charges, and allowed rent.

Reproduce the supplied underwriting layout

The Spreadsheet Layout Block defines where each fact belongs. Copying its structure exactly keeps every calculation tied to the supplied model.

Return to the Google Sheets browser tab from earlier.
Open only the supplied block headed Spreadsheet Layout Block.
Keep the Reality Block closed.
Keep the Check section closed.
Reproduce the Spreadsheet Layout Block exactly in your underwriting workbook.

What Does Exact Reproduction Mean?

Every section stays in the supplied order.
Every label keeps its supplied wording.
Every input location remains available for a released fact or an unknown.
Every output remains in its supplied position.
The calculation order stays unchanged.

Your blank workbook now has a complete underwriting structure. It is ready to separate released facts from unresolved gaps.

Compare the Google Sheet with the Spreadsheet Layout Block line by line.
Correct each structural difference before adding simulation facts.

Gather sourced facts from every simulated person

Each simulated person holds a different part of the deal record. A source label shows where each fact came from without giving that fact more certainty than its source provides.

Before you ask, do you think a broad request for everything important will fill every unknown in the model?

Return to the fictional simulation chat from earlier.
Ask the simulated agent for all remaining information they have about the selected duplex.
Ask the simulated seller to add any important facts about the selected duplex.

You will still see unanswered categories in your model. That shortfall is intentional because broad requests rarely expose every decision-critical fact.

Keep the Simulation Fictional

Every agent, seller, lender, and inspector in this chat is simulated. The conversation supplies fictional facts without creating a real quote, application, offer, order, payment, or professional contact.

The AI releases information only. You remain responsible for every calculation and decision.

Return to the Texas Duplex House Hack Decision Log in Google Docs.
Add an Underwriting Fact Log heading.
Record each newly released fact under its topic.
Label each fact as coming from the simulated agent, seller, lender, or inspector.
Note whether each fact was volunteered or released after a focused question.

Why Keep a Sourced Fact Log?

A source label creates a trail from each spreadsheet input back to the simulated person who supplied it. An unknown stays visible until that person releases the missing fact.

This trail prevents a persuasive property summary from turning into an unsupported spreadsheet assumption.

Ask the simulated agent about the property facts.
Ask the simulated agent about the existing leases.
Ask the simulated agent about support for the released rents.
Ask the simulated agent about utility responsibility.
Ask the simulated agent which property claims still require buyer verification.
Ask the simulated seller about disclosures.
Ask the simulated seller about ownership.
Ask the simulated seller about prior work on the property.

What Should the Property Record Show?

The property record should distinguish released facts from unresolved questions. No unknown gets converted into a convenient estimate.

Ask the simulated lender to break down every part of the monthly payment.
Ask the simulated lender how mortgage insurance applies to the supplied financing path.
Ask the simulated lender for the cash to close information.
Ask the simulated lender for the reserves information.
Ask the simulated lender about the owner occupancy requirements.

Follow the Financing Trail

The monthly payment shows the ongoing housing burden. Cash to close shows the amount needed to complete the fictional purchase.

Reserves show the simulated liquidity left after closing. Each figure answers a different risk question.

Ask the simulated lender how rental income is treated.
Ask the simulated lender which documents show where the money came from.
Ask the simulated lender about the consequences of the appraisal.
Ask the simulated lender about differences among the supplied funding paths.

Keep Financing Facts Separate

Record only financing details released by the simulated lender. Funding comparisons and the final financing choice belong to the next phase.

Ask the simulated inspector about the structure.
Ask the simulated inspector about the roof.
Ask the simulated inspector about the foundation.
Ask the simulated inspector about water conditions.
Ask the simulated inspector about drainage.
Ask the simulated inspector about the electrical system.

Treat Physical Findings as Deal Facts

An inspection examines physical condition. Its released findings belong in the fact log before they influence a calculation or decision.

Ask the simulated inspector about the plumbing.
Ask the simulated inspector about the heating and cooling systems.
Ask the simulated inspector about safety conditions.
Ask the simulated inspector about deferred maintenance.
Ask the simulated inspector about any follow-up inspections.
Keep every unreleased item marked unknown.
Move each possible real-world follow-up to the Outbox.
Mark every new Outbox item as public research only with no live deal.

Calculate the live-in result

The spreadsheet now has two kinds of evidence. Released facts become inputs while unresolved items remain visible as unknowns.

Switch back to the Texas Duplex House Hack Underwriting Google Sheet.
Transfer every released property fact into its matching input.
Transfer every released lease fact into its matching input.

You should see the selected duplex begin to replace blank inputs with sourced simulation facts.

Transfer every released rent fact into its matching input.
Transfer every released utility fact into its matching input.
Compare the populated property inputs with the Underwriting Fact Log.

Each populated property input should match a fact in the decision log. Missing facts should remain visibly unknown.

Transfer every applicable financing fact into its matching input.
Transfer the released cash-to-close information into its matching input.
Transfer the released reserves information into its matching input.

What Belongs in the Financing Inputs?

The PITI components come only from the simulated lender.
The mortgage insurance input comes only from the simulated lender.
Any other required monthly charge comes from the supplied model and released financing facts.
Cash-to-close information stays separate from the monthly payment.
Reserves information stays separate from cash to close.

Label every populated input with its simulated source.
Mark every unreleased input as unknown.
Scan the spreadsheet for any estimate that was not released by the simulation.

You should see a source beside every populated input. Any unsupported value should be removed from the model.

Calculate PITI in the order directed by the supplied model.
Calculate the full monthly payment by including mortgage insurance and every other required monthly charge in the supplied model.

You should see one full monthly payment built from the released financing inputs. Mortgage insurance should remain visible within that result.

Before you reveal the live-in comparison, do you expect the sourced calculation to support your original prediction?

Calculate the monthly cost of living in one unit after applying only the other unit's allowed rent.
Compare the live-in monthly cost with the apartment rent from Your Position.

You will see whether the duplex costs less than, the same as, or more than the apartment while you occupy one unit. Keep the original prediction unchanged beside this calculated result.

Confirm that every populated spreadsheet input traces to a simulated agent, seller, lender, or inspector disclosure.
Confirm that every unreleased input remains marked unknown.
Confirm that the full monthly payment includes mortgage insurance.
Confirm that the live-in monthly cost uses only the allowed rent from the other unit.
Confirm that the apartment comparison shows a clear monthly result.
Confirm that the buy box, walk-away point, and original prediction remain unchanged.
Confirm at minute 26 that the Reality Block and Check section remain closed.

You now have a sourced live-in result that separates released facts from unknowns. Next, you will compare funding paths before making the fictional offer.

Compare Funding and Negotiate

Your underwriting in Google Sheets now shows how the selected duplex compares with your apartment. You also have sourced facts for the property plus its financing.

Expensive capital can erase a promising live-in result. Lost liquidity can leave the buyer without enough room for repairs or surprises.

Retirement consequences can weaken a funding plan. Partnership conflict can make the same plan unworkable.

Truthful owner occupancy sets a firm boundary for every option. This phase keeps each choice fictional while you compare funding plus negotiate within your walk-away point.

In this step, get ready to:

Compare at least three funding paths from Your Position.
Choose one path using cost, liquidity, risk, plus owner-occupancy duties.
Negotiate a fictional price with a closing-cost credit inside your walk-away point.

Compare at least three funding paths

A funding path explains where the purchase money comes from. A complete comparison also shows what each option costs after closing.

What Belongs in Each Comparison Entry?

Required cash: the amount needed from the learner's available resources.
Ongoing cost: the financing expense that continues after closing.
Repayment or ownership obligation: what must be repaid or shared.
Reserve effect: the amount of reserves left after the purchase.
Main risk: the biggest financial or relationship weakness in the path.

Switch back to the existing Google Docs decision log.
Create a section titled Funding Comparison beneath the sourced fact log.

The decision log now has a dedicated place to keep funding evidence separate from property facts.

Add at least three possible funding paths using only resources listed in Your Position.
Complete the five comparison fields for every path.

You should now see at least three entries with the same five fields. Any gap remains visible instead of becoming an estimate.

Mark every unreleased funding detail as unknown.
Compare each path with the cash limits already recorded in your buy box.

Your comparison now shows which options preserve liquidity. It also exposes any path that strains the limits you set before seeing the duplex.

Keep Real Funding Questions in the Outbox

Retirement money deserves a hard pause before any real use. If a path touches a Roth IRA, its tax treatment depends on the account facts.

Real retirement questions require review by a CPA plus the relevant plan administrator. Partnership terms also require professional review outside this fictional exercise.

Add tax, retirement, title, partnership, gift, money-source, eligibility, plus agent-agreement questions to the Outbox.
Label those entries as public research only with no live deal.

The Outbox now separates unresolved real-world questions from the fictional decision.

Add CPA review as a required follow-up for any retirement or tax question.
Add plan-administrator review as a required follow-up for any retirement-plan question.

Your three-path comparison is complete. Each option now carries its full cash commitment plus its main risk.

Choose and test one financing path

The strongest path fits the spreadsheet while preserving enough flexibility for the deal's unknowns. Its occupancy duties must also match your real intention inside the simulation.

How Should You Choose?

Cost shows what the funding adds to the deal.
Liquidity shows how much usable cash remains.
Risk shows what could make the path fail.
Occupancy duties show whether the financing matches the learner's truthful plan.

Review the completed comparison to identify the path that best fits all four tests.
Create a section titled Selected Funding Path in the decision log.

You now have one place to record the decision without changing the original buy box or prediction.

Write a rationale covering cost, liquidity, risk, plus truthful occupancy duties.

That is a meaningful checkpoint. Your financing choice now has a written reason that can be audited after the simulation ends.

What Must the Simulated Lender Know?

The selected path only holds up when the simulated lender receives the complete scenario. Keep the disclosure factual by using Your Position plus the unchanged occupancy plan.

Existing rentals shown in Your Position.
Available cash shown in Your Position.
Other accounts shown in Your Position.
Any coworker involvement shown in Your Position.
Intended owner occupancy.
Expected move-out timing.

Switch back to the existing AI chat client to continue the controlled simulation.
Send one fictional disclosure message covering every item in the checklist before requesting the supplied financing facts.

The simulated lender should now respond to the complete scenario. The lender supplies facts while you retain the financing decision.

Record a summary of your truthful disclosures in the decision log.
Enter each released selected-financing input with its lender source label in the matching spreadsheet field.

Your spreadsheet should recalculate its affected outputs from the released inputs. Every remaining unknown stays visibly marked.

Review the recalculated payment, cash-to-close, plus reserve outputs.
Move every unresolved financing question into the Outbox.

Your selected path has now survived a truthful lender test. No real lender contact or quote has occurred.

Make and negotiate the fictional offer

A seller credit is the amount the seller agrees to contribute toward closing costs. Its effect belongs in the supplied cash to close calculation.

Keep the Offer Fictional

Sending an offer can feel like a real commitment. This exchange stays inside the simulation with no application, signature, payment, quote, or contact outside the fictional chat.

Switch back to the underwriting spreadsheet to identify an opening price supported by your calculations.
Record that opening price in a new fictional-offer entry in the decision log.

The opening price is now tied to your own analysis instead of the seller's preference.

Use the spreadsheet to determine the requested seller credit.
Record the requested credit beside the opening price.

Your fictional offer now has two explicit terms that can be measured against the deal.

Compare both opening terms with the unchanged walk-away point.

Before you send the offer, do you expect the simulated seller to accept it or return counterterms?

Send the fictional opening price plus requested seller credit to the simulated seller.
Record the simulated seller's response in the decision log.

You should now have either an acceptance or a set of counterterms. That response becomes the next input to your analysis.

Keep Control of the Negotiation

Every changed price or credit can alter several spreadsheet outputs. Recalculating before each response keeps the walk-away point in control.

Enter each simulated counterterm into the matching spreadsheet inputs.
Review the recalculated affected outputs.
Compare the revised result with the unchanged walk-away point.

The spreadsheet now shows the financial effect of the seller's terms before you answer.

Send your fictional response based on the recalculated result.
Record the simulated seller's final response on price plus closing-cost credit.

The negotiation record now preserves the opening terms, any counterterms, plus the seller's final position.

Enter the final simulated price into its matching spreadsheet input.
Enter the final simulated seller credit into its matching spreadsheet input.

Your underwriting spreadsheet should now display the affected outputs under the final fictional terms.

Review every recalculated affected output.
Record your acceptance or continuation decision in the decision log.

Before this final check, do you expect every funding term to match between the decision log, simulation chat, plus spreadsheet?

Check that the funding comparison contains at least three complete paths.
Check that the selected-path rationale covers cost, liquidity, risk, plus occupancy duties.
Check that the decision log records every truthful simulated lender disclosure.
Check that the negotiation record contains the opening terms, counterterms, final price, final credit, plus your decision.
Check that the spreadsheet contains the released financing inputs plus recalculated affected outputs.
Confirm that the buy box, walk-away point, plus original prediction remain unchanged.
Confirm that the Reality Block plus Check remain closed.

What Should You See at Minute 38?

At least three funding paths with the required cash, ongoing cost, obligation, reserve effect, plus main risk.
One selected path with a written reason grounded in the four decision tests.
A complete record of truthful fictional lender disclosures.
The simulated seller's final response on price plus closing-cost credit.
Updated spreadsheet outputs based on the final fictional terms.

You have kept the financing honest while negotiating from your own numbers. The fictional deal now has terms you can carry into closing analysis.

Your funding plan plus fictional negotiated terms are recorded. Next, you will test whether the deal survives a closing problem plus its first year of operations.

Resolve Closing and First-Year Operations

You protected truthful owner occupancy throughout the funding comparison. Your fictional offer now has a negotiated price plus seller credit.

A negotiated offer can still lose viability at closing. You will use the unchanged walk-away point plus your own calculations to handle that pressure.

A first-year setback tests whether the property remains durable after the fictional closing. The game master releases facts plus consequences while every response stays yours.

In this step, get ready to:

Analyze the simulated closing problem against your walk-away point.
Reconcile the final fictional closing figures.
Handle the first-year setback through your own calculations.

Solve the closing problem

The closing problem tests whether the negotiated deal still fits the limits you wrote before seeing any property. The simulation supplies the event while you own the analysis.

Before you reveal the problem, which part of the fictional deal do you expect it to pressure?

Switch back to the existing AI chat from earlier.
Ask the game master to release the simulated closing problem without recommending a response.

You should receive one closing problem containing only the facts supplied by the simulation. The response should leave the decision to you.

Return to the decision log from earlier.
Add the heading Fictional Closing and First-Year Operations.

You should now see a dedicated section for the closing analysis plus the operating record.

Record the supplied closing problem beneath the new heading.
Add each released closing fact to the underwriting fact log.

Your records should now separate the supplied problem from the facts used to analyze it.

Mark every unreleased closing detail as unknown.
Enter each released closing fact into its matching spreadsheet input.

The spreadsheet should now contain only sourced closing facts plus visible unknowns.

Calculate the problem's financial effect in the category released by the simulation.

Your spreadsheet should now show the problem as a cash effect, monthly effect, reserve effect, or value effect.

Keep the calculation scoped

The simulation determines which financial category the problem affects. Only released facts belong in the calculation.

The result may change cash to close, monthly payment, reserves, or property value. Every unreleased input remains unknown.

Compare the calculated effect with the original walk-away point.
Choose the fictional response supported by your analysis.
Explain the choice to the appropriate simulated person.

The simulation should return the fictional consequence of your choice. That consequence becomes a new released fact.

Record the closing decision beneath your calculation.
Record the released consequence beneath the decision.

That is a meaningful checkpoint. Your fictional closing now has a decision tied to the rule you wrote before seeing the outcome.

Reconcile the fictional closing

Closing reconciliation makes every final figure traceable to the latest simulated information. Any unexplained difference stays visible until the simulated lender supplies a fact-based explanation.

Return to the underwriting spreadsheet from earlier.
Enter each final released closing figure into its matching input.

Your final inputs should now show the simulated price, seller credit, plus financing terms.

Recalculate the full monthly payment through the supplied model.
Recalculate cash to close through the supplied model.

You should now see final PITI, mortgage insurance, full monthly payment, plus cash to close.

Calculate the remaining reserves after the fictional closing.
Carry the previously calculated closing-problem effect into its matching output.

The spreadsheet should now show final remaining reserves plus the financial effect of the closing problem.

Compare every final figure with the most recent simulated lender information.
Flag each difference that lacks a released explanation.
Ask the simulated lender to explain each flagged difference without requesting a recommendation.
Add each released explanation to the underwriting fact log.

You should see either matching figures or a sourced explanation beside every difference. No unexplained amount should disappear into an assumption.

Closing language can feel real, so this boundary deserves extra care.

Add every new real-world transaction action to the Outbox.
Add every new real-world property action to the Outbox.

Your Outbox should now include signatures, applications, orders, payments, wires, lender contacts, professional contacts, inspections, appraisals, tenant actions, plus property actions.

Label each new Outbox entry as public research only with no live deal.
Mark each new Outbox entry as undone.

Strong work. The fictional closing figures now tell one traceable story across the spreadsheet, decision log, fact log, plus Outbox.

Run the first year

The first-year sequence tests whether the property can absorb an operating setback. Your response changes the simulated cash flow only after you compare the available options.

Before you advance the simulation, where do you expect the first-year setback to put the most pressure?

Ask the game master to advance the fictional first year without recommending a response.

You should receive a supplied operating setback containing facts that you can analyze. The simulation should stop before choosing a response.

Keep the decision yours

A recommendation from the simulation falls outside the game master's role. Your calculations must drive the response.

Discard any recommended choice.
Ask the simulation to restate only the supplied facts plus consequences.
Make the response decision from your own calculations.

Return to the fictional closing section in the decision log.
Record the supplied first-year setback beneath the closing record.

The decision log should now preserve the operating event exactly as the simulation released it.

Add every released event fact to the underwriting fact log.
Mark every unreleased event detail as unknown.

Your fact log should now distinguish the supplied first-year information from every remaining unknown.

List the realistic response options in the decision log.
Calculate the immediate financial effect of each option.

Your option comparison should now show the immediate cost or benefit attached to each response.

Calculate the monthly financial effect of each option.
Compare the completed option calculations.

You should now see how each response affects the property immediately plus month by month.

Apply fair housing law to any simulated tenant decision.
Select the response supported by your calculations.
Tell the appropriate simulated person which response you chose.

The simulation should release the consequence of your response. Treat that consequence as a new sourced fact.

Enter the released financial consequence into the matching spreadsheet output.
Record the chosen response plus its consequence in the decision log.

That completes the operating test. The spreadsheet now carries the event's financial effect instead of leaving it buried in the chat.

Before the minute-48 check, do you expect the spreadsheet plus decision log to tell the same financial story?

Return to the decision log at minute 48.
Check the closing-problem analysis against the spreadsheet.
Check the first-year event record against the spreadsheet.
Confirm every new real-world follow-up appears in the Outbox.

Your notes should show the closing calculation, closing decision, first-year setback, selected response, plus released consequence. Your spreadsheet should show the matching financial effects.

Confirm the original buy box remains unchanged.
Confirm the original walk-away point remains unchanged.
Confirm the original two-part prediction remains unchanged.
Keep the Reality Block closed.
Keep the supplied Check section closed.
Confirm the owner-occupancy intent remains truthful.

You should now see a complete fictional record covering the closing problem, final closing figures, first-year setback, response calculations, chosen response, plus financial consequence.

Your fictional deal has now survived closing plus its first operating setback. Next, you will test both end states against the prediction you refused to rewrite.

Secret mission

Complete the Exit Audit

This final audit freezes your original decision rules. You will test the live-in result against the move-out result. The finished record includes Reality Block comparisons, supplied-rule scores, a 60-word lesson, a ledger line, and a complete Outbox.

Clean Up Your Resources

Your fictional deal created only browser-based study files with no ongoing costs. Choose the cleanup option that fits what you plan to do next.

Resources you used:

A Google Sheets file titled Texas Duplex House Hack Underwriting containing the fictional underwriting model.
A Google Docs file titled Texas Duplex House Hack Decision Log containing the decisions, scores, lesson, ledger line, and Outbox.
One conversation in your existing AI chat client containing the controlled fictional simulation.

Keep everything running

No action is needed. Choose this if you want to revisit your calculations or review how the original prediction compared with the final outcomes.

Keep the Texas Duplex House Hack Underwriting spreadsheet as your completed underwriting record.
Keep the Texas Duplex House Hack Decision Log document as your decision record.
Keep the fictional simulation conversation as a record of released facts and consequences.
Leave every item in the Outbox unperformed.

Pause - I'll come back to this later

Google Docs Editors saves your Google Sheets and Google Docs changes automatically while you are online. Pausing closes the browser tabs without deleting the fictional work.

Close the Google Sheets browser tab.
Close the Google Docs browser tab.
Close the AI chat browser tab.
Leave the Outbox untouched until you intentionally resume the fictional study.

Delete - I don't want to use this again

This option removes the spreadsheet, decision log, and fictional simulation conversation. It suits a clean finish when you do not plan to revisit the audit.

Deletion Is Permanent

These deletions permanently remove your underwriting work and simulation history. Files outside this project remain unchanged.

Switch back to the Google Sheets file titled Texas Duplex House Hack Underwriting.
Use the file controls in Google Sheets to move Texas Duplex House Hack Underwriting to trash.
Use the trash controls for your Google files to permanently delete Texas Duplex House Hack Underwriting.
Confirm that Texas Duplex House Hack Underwriting no longer appears in the trash area.
Switch back to the Google Docs file titled Texas Duplex House Hack Decision Log.
Use the file controls in Google Docs to move Texas Duplex House Hack Decision Log to trash.
Use the trash controls for your Google files to permanently delete Texas Duplex House Hack Decision Log.
Confirm that Texas Duplex House Hack Decision Log no longer appears in the trash area.

The spreadsheet and decision log are now removed. The simulation conversation is the final fictional record.

Switch back to the controlled fictional simulation in your existing AI chat client.
Use the conversation controls to permanently delete that simulation conversation.
Confirm that the deleted simulation no longer appears in your conversation history.

All three fictional project artifacts are now removed. No real loan, quote, offer, contract, inspection, appraisal, tenant action, transfer, or paid resource was created.

Nice Work!

Outstanding work! You completed a fictional Texas duplex house hack from initial decision rules through the final exit audit without handing your calculations or choices to the AI.

You've learned how to:

Define a buy box plus a walk-away point before viewing any simulated option. Screen every duplex while keeping missing information visibly unknown.
Build a sourced underwriting spreadsheet from released facts. Calculate the full monthly payment with mortgage insurance. Compare the live-in monthly result with the apartment rent.
Compare at least three funding paths before selecting a truthful financing plan. Negotiate a fictional price plus a seller credit. Resolve the closing problem plus the first-year setback with your own calculations.
Secret Mission: Completed the exit audit without changing the original decision rules or prediction. Compared the live-in and move-out outcomes with the Reality Block. Applied the supplied scoring rules. Recorded an exactly 60-word lesson. Completed one ledger line.

Ready to quiz yourself?