# Ten original source pairs · Days 11–20

**All people, organisations, offers, messages and numbers on this page are invented classroom models.** Dollar amounts are fictional Australian dollar values. The public line and desk note are separate constructed texts, not competing real testimonies. No one should spend money, disclose a household budget or treat a model as an employment, tax or investment offer. Read aloud, enlarge, transcribe to Braille or place each numbered fact on a tactile card as needed; record that support. The learner's job is to identify **who says what to whom**, calculate within the stated units, and publish only a conclusion the model can support. The [public checks](STUDENT-CHECKS.md) use different cases.

## Day 11 · Planetarium cards · visual exhibit

**Public notice, by fictional Orbit Hall editor to visitors:** “Choose our 50-card constellation set. It is the cheapest way to build any night-sky wall. Big ideas deserve the big bundle.” The word *any* makes a promise beyond one order size.

**Desk note, invented prices before any delivery charge:** Set S contains **25 cards for $20**. Set L contains **50 cards for $35**. Sets cannot be split at purchase. A paper exhibition needs **40 cards**; a small trial needs **20**. Every card in this model is identical. Delivery is **unknown**, not $0.

**Inquiry:** Find each per-card price and the lowest stated whole-set outlay for 20 and 40 cards. What can the editor truthfully say to each audience? [Optional whole-set calculator](interactive/whole-set-lab.html); [paper route](interactive/TEXT-ROUTE.md).

## Day 12 · Archive guide pay line · adult work model

**Public recruitment draft, by fictional museum editor to adult applicants:** “A steady $1,120 in your pocket every week. Join the label archive team.” The phrase *in your pocket* suggests take-home money.

**Desk note:** This invented **gross annual salary is $58,240**. For this exercise divide by **52 weeks**. No tax, deductions, allowance, work-hours or eligibility information is supplied. This is **not** a pay entitlement statement or legal wage example.

**Inquiry:** Compute gross weekly model pay, distinguish it from take-home pay, and rewrite the invitation with the missing boundary.

## Day 13 · Route-clue cards · recreation kit

**Public handout, by fictional Trail Table organiser to club members:** “No setup fee? That must cost less, whatever the number of clue cards.” The question mark invites readers to accept a shortcut.

**Desk note:** Plan A has a **$12 fixed setup charge plus $0.40 per card**. Plan B has **no setup charge and $0.65 per card**. Compare **40 cards** and **60 cards**. These are printing-only model costs; postage and card quality are unknown.

**Inquiry:** Write both total-cost rules, compare each specified quantity and produce a conditional recommendation rather than an “always” claim.

## Day 14 · Mini-garden workshop · event budget

**Public invitation, by fictional workshop committee to participants:** “Our whole $380 pool is ready for your new project ideas. Tell us what to buy.” The word *whole* makes already committed money sound available.

**Desk note:** Fictional pool **$380**. Fixed commitments: room **$140**, table hire **$90**. Proposed optional paper-and-pencil materials **$80**. These are model categories, not quotes or a real community budget. No other costs are supplied.

**Inquiry:** Separate fixed from discretionary amounts, calculate the remaining uncommitted balance before and after the proposal, and edit the invitation so participation is real without promising unavailable funds.

## Day 15 · Science-exhibit reserve · simple-interest model

**Public message, by fictional exhibition treasurer to committee:** “The $1,200 paper-equipment reserve earns 3% every month. After two years it will grow fast enough for any upgrade.” The time unit and “any” both outrun the note.

**Desk note:** Classroom-only **simple interest**: principal **$1,200**, rate **3% per year**, time **2 years**. Use `interest = principal × annual decimal rate × years`; add interest to principal for the model ending balance. No fees, compounding, price inflation or real product are modelled.

**Inquiry:** Calculate interest and ending balance, name the wrong time unit in the public line, and replace the prediction with a bounded numerical claim. The separate [Check A](STUDENT-CHECKS.md) uses a fresh source after this lesson.

## Day 16 · Recipe-card archive · discounted printing

**Public comparison, by fictional club editor to members:** “The $99 printer is clearly the cheapest. Why pay the other shop's $120?” The comparison selects one visible sticker price.

**Desk note:** Option A has a sticker price **$120**, a **15% discount on that price**, and no listed setup charge. Option B has a sticker price **$99** and a mandatory **$8 setup charge**. Delivery and print quality are unknown for both; do not treat unknown as free or equal.

**Inquiry:** Calculate the two stated totals, show the discount base, and revise *clearly* to account for both the known result and unknown terms.

## Day 17 · Costume-sleeve packing · adult work model

**Public recruitment card, by fictional theatre storekeeper to adult helpers:** “Paid by the piece is the better way to earn for a four-hour shift. More work, more reward.” This is a constructed comparison, not a real job ad.

**Desk note:** Model H pays **$24 per hour for 4 hours = stated gross pay**. Model P pays **$11 per accepted sleeve**, with **8 accepted sleeves** in the stated shift. Rejected work, minimum employment entitlements, tax and other conditions are **not** modelled. Do not use the card to advise on actual employment.

**Inquiry:** Compare stated gross pay for this one shift, identify the condition that determines piecework pay, and write a safe one-shift comparison instead of *better* without scope.

## Day 18 · Sports-scoreboard parts · fully taxable GST model

**Public price card, by fictional parts catalogue to a coach:** “$75 is your final total for Option A. Our small print is simple.” The word *final* matters.

**Desk note:** In this teaching scenario **both listed parts are assumed fully taxable under Australian GST**, with no delivery or discount. Option A is **$75 GST-exclusive**. Option B is **$86 GST-inclusive**. The [ATO rule](https://www.ato.gov.au/law/view/document?locid=%27PAC%2F19990055%2F9-75%281%29%27) supports using 10% of a fully taxable GST-exclusive value (equivalently 1/11 of its GST-inclusive price). This card does **not** classify any real product or issue tax advice.

**Inquiry:** Add GST to A, compare final listed totals, and rewrite the catalogue sentence with the fully-taxable assumption and missing delivery boundary.

## Day 19 · Podcast paper-planning fund · repeatable budget

**Public planning line, by fictional podcast-club convenor to members:** “We can repeat this plan forever with $35 left each week. No other question is needed.” The word *forever* erases changing costs.

**Desk note:** One invented week has a **$210** allocation, **$120 fixed** room and equipment charges and **$55 discretionary** paper planning materials. For a four-week *what-if*, suppose these three amounts remain exactly the same each week. No fifth week, prices, tax or actual club funding is evidenced.

**Inquiry:** Calculate the one-week balance and conditional four-week balance. Then draft a source-bound planning line that asks what would need rechecking.

## Day 20 · Printmaking poster · sequential percentages

**Public sign, by fictional gallery tutor to adult makers:** “A 25% markup followed by a 10% discount returns the poster to its $40 making cost. The two percentages cancel.” The verb *cancel* conceals two different bases.

**Desk note:** In this constructed model, making cost is **$40**. First add **25% of $40** to make the marked price. Then discount **10% of that new marked price**. There are no other charges or tax. This is a classroom price exercise, not actual retail advice.

**Inquiry:** Show both bases and the final price; identify the text choice that makes the arithmetic sound simpler than it is. Create a two-sentence correction for a reader. The separate [Check B](STUDENT-CHECKS.md) uses a fresh source after this lesson.

**Original resource rights:** © NeuroForgeIO Pty Ltd 2026, SubjectNest, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). Credit author, source, licence and changes. The linked QCAA and ATO material retains its own rights.