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Primary General Studies | Money management and smart shopping guide | Needs, unit price and four common errors
P4 students usually call a want a need, and they say it with confidence: I need new trainers because the old ones are not nice any more. Do not answer with a moral judgement. Use a test anyone can check: without it, does daily life or learning stop, or are you just unhappy? The other essential arithmetic is unit price, because a bigger pack is not always cheaper. Five hundred millilitres for 8 dollars is 1.6 dollars per 100 millilitres, while one litre for 14 dollars is 1.4 dollars. A student who computes this once needs far less reminding to compare prices.
Objectives — Students can (1) separate needs from wants with the question about whether life or learning is affected, and justify their own sorting; (2) compare two packs by unit price per 100 millilitres and state the difference; (3) calculate 15 dollars a week over 52 weeks as 780 dollars, explain interest as payment for lending money, and work out the real price per item in a buy two get one free offer.
01 Prerequisites (3-minute check)
If any of these fails, fix it before the lesson starts.
| Skill | Quick check | Pass mark |
|---|---|---|
| A year has 52 weeks | Saving 15 dollars a week, how much in a year? | 780 dollars |
| Division with decimals | 8 dollars for 500 millilitres: how much per 100 millilitres? | 1.6 dollars |
| A percentage means per hundred | What is 2 percent of one hundred dollars? | 2 dollars |
02 Lesson flow (45 minutes)
| Time | Stage | Tutor does | Student does |
|---|---|---|---|
| 0-5 min | Opening judgement | Ask which items on a list are needs and which are wants, and hold the answers | Do not mark them right or wrong yet |
| 5-16 min | Needs and wants | Test each item with three questions and allow in-between answers with reasons | Never use the word wasteful about a student choice |
| 16-26 min | Unit price | Compute 500 millilitres at 8 dollars against one litre at 14 dollars, both per 100 millilitres | Units must be written or the comparison means nothing |
| 26-34 min | Saving and interest | 15 dollars a week is 780 dollars a year; 1,000 dollars at 2 percent earns 20 dollars | Keep to one year and simple interest only |
| 34-41 min | Advertising tricks | Unpack three tricks: buy two get one free, limited edition, crossed-out prices, and restore the real unit price | Buy two get one free at 15 dollars is 30 dollars for three, so 10 each |
| 41-45 min | Exit check | Three spoken items and one written item | See section eight |
03 Teaching script (read it out)
Scene 1: Needs and wants: a test you can check
Do not open with the word wasteful; students stop talking once they hear a judgement. Use three questions instead. Without it, does daily life stop? Without it, is your learning affected? Without it, are you merely unhappy? A yes to either of the first two makes it a need; three noes make it a want. Model the honesty first by admitting one of your own wants, such as an expensive pen because it looks good. That makes it safe for students to answer truthfully. Then take the hardest case, trainers: a pair for PE is a learning need, a second limited-edition pair is a want. One object can hold both, and telling them apart is exactly what P4 should learn.
Close by asking students to re-test the opening list with the three questions and cross one item out.
Scene 2: Unit price: make two packs the same unit
Act two has one technical move: divide the price by the amount so both packs share a unit. Five hundred millilitres at 8 dollars is 1.6 dollars per 100 millilitres. One litre, which is 1,000 millilitres, at 14 dollars is 1.4 dollars per 100 millilitres, so the large pack is 0.2 dollars cheaper per 100 millilitres, which is 16 dollars against 14 dollars per litre. Ask students why the unit matters: comparing prices of different amounts compares two different things. Then break the assumption that bigger is always cheaper by putting a small special on the board, 250 millilitres at 3.5 dollars, which is also 1.4 dollars per 100 millilitres, so the large pack has no advantage at all. The same method works for tissues, rice and laundry liquid.
Close by asking what they would do if the large pack were dearer per 100 millilitres.
Scene 3: Saving, interest and advertising
Act three turns saving into a number. Pocket money of 50 dollars a week with 30 percent saved is 15 dollars, and 52 weeks gives 780 dollars, which students should multiply themselves because they consistently underestimate small regular saving. Interest stays at one simple layer: 1,000 dollars at 2 percent a year earns 20 dollars, and interest is payment for lending money, not a gift. Skip compound interest, which at P4 only creates confusion. Finish by unpacking offers: buy two get one free at 15 dollars means paying 30 dollars for three, so 10 dollars each; limited editions and crossed-out prices create time pressure and a price illusion without changing what the item is worth. Students should be able to say I may still buy it, but I know what each one costs me.
Close by asking for the price per item in a buy two get one free offer, and recomputing if it is wrong.
04 Question types and worked steps
| Type | Example | Steps | Answer |
|---|---|---|---|
| Sorting | Sort six items into needs and wants with one reason each | Apply the three questions, mark in-between cases, write the reason | A label with no reason scores nothing |
| Calculation | Which is cheaper per 100 millilitres, 500 millilitres at 8 dollars or one litre at 14 dollars, and by how much? | Convert both to per 100 millilitres, subtract, give units | 1.4 dollars against 1.6, a difference of 0.2; no units loses a mark |
| Application | Saving 15 dollars a week, how much in a year? | Multiply 15 by 52 and give units | 780 dollars; multiplying by 12 months is the usual error |
| Judgement | In a buy two get one free offer at 15 dollars each, what does each item really cost? | Multiply 15 by 2 to get 30, divide by 3, then state it is a per-item price | 10 dollars; free means the offer was misread |
Sanity check (teach this): Sanity check: three lines hold the chapter, sorting with three questions, comparing by one unit, and accumulating by multiplying weeks, and each has a checkable calculation or sentence rather than a character judgement. Every price and volume is a classroom example and is labelled as such, so nobody treats them as current shop prices. Interest is one year of simple interest, with no compounding, credit cards or borrowing, since P4 has no framework for risk. The advertising section unpacks methods only and never names a brand. In-between cases must stay, otherwise students learn to relabel every want as a need to avoid criticism.
05 Independent practice (3 questions)
| Question | Answer | What to watch |
|---|---|---|
| Sorting with reasons | Sort six items and explain two in-between cases | The reason must use one of the three questions |
| Unit price | Compare 250 millilitres at 3.5 dollars with one litre at 14 dollars | Both are 1.4 dollars per 100 millilitres, so the same |
| Saving | Saving 20 dollars a week, how much in half a year of 26 weeks? | 520 dollars, with units |
06 Common mistakes and what to say
| Mistake | Student writes | Say this |
|---|---|---|
| Calling every want a need | I need these shoes because I like them | Liking them makes it a want. The pair you need for PE is the need. One thing can have both parts, and your job is to tell which is which. |
| Comparing prices without comparing amounts | One litre at 14 dollars is dearer than 500 millilitres at 8 dollars | The amounts differ, so comparing the prices compares two different things. Convert both to the same unit, for example per 100 millilitres. |
| Underestimating small regular saving | Saving 15 dollars a week is only a hundred or so a year | 15 times 52 is 780, close to a pair of ordinary trainers. Small amounts add up over a year; multiply it once and you will see. |
| Believing buy two get one free means a free item | Buy two get one free means one of them costs nothing | You pay 30 dollars and take three, so each costs 10 dollars. It is cheaper, not free, and if you did not need it you still spent 30 dollars. |
07 Homework (paper, section and question numbers)
- Independent practice in this chapter, with answers — Use practice items 1 to 3, plus two written items: compare the unit price of three household items at home, and compute a year of your own weekly saving
- Primary General Studies paper for mixed practice — For revision week mixed practice; the paper has no money items, so treat it as question-reading and answer-format training
08 Exit check (last 5 minutes)
| Question | Answer | Decision |
|---|---|---|
| How do you tell a need from a want | Use the three questions: does life stop, is learning affected, or are you just unhappy | One of the three questions must be quoted |
| Which is cheaper, 500 millilitres at 8 dollars or one litre at 14 dollars | The litre, at 1.4 against 1.6 per 100 millilitres | Both unit prices must be stated |
| How much is 15 dollars a week for a year | 780 dollars | 180 dollars means months were used; recompute on the spot |
09 Tutor FAQ
Families differ in income, so will a money lesson embarrass some students?
It can, so avoid words like wasteful, poor or cannot afford throughout. Use neutral items such as tissues, rice and stationery, and say plainly that every family chooses differently and today is about counting and sorting, not judging. The sorting task uses each student own list and nobody is asked to share it aloud.
Should electronic payment and online shopping come up?
One sentence is enough: paying by phone hides the moment of paying, so it is easier to buy more. Do not expand, and name no platform or promotion. The core of P4 remains unit price, saving and advertising methods, all of which can be calculated.
Should compound interest be taught?
No. P4 covers one year of simple interest, principal times rate. Compounding belongs to secondary school; at this age it turns into a shortcut fantasy of money growing by itself, which works against a lesson on careful spending.
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A TutorZone lesson-prep guide. Written by the TutorZone team; questions and lesson flow are original and are not taken from any school or publisher material.