Buying paint for a project
You need paint for one poster. A small pot is $2. A big pot, four times the size, is $5. You will use about a small pot’s worth.
Which do you buy?
Step 1: What Would You Do?
There is often more than one good answer. Pick one and see what happens.
Step 2: What That Was
The name for what you just worked out.
Cheap means the price is low. Good value means you get a lot for the price. They are not the same thing.
Value is how much you get for what you pay.
Compare the same amount
Two bags of different sizes cannot be compared by price alone. Work out what one of something costs in each, and then they can be.
The big one is not always better
A bigger pack is usually better value. Not always — and if you cannot use it all, the value goes in the bin with the rest.
Step 3: Try It
These ones do have right answers.
Work Out the Value
1 of 2
6 apples for $3. How much is one apple, in cents?
cents
2 of 2
A big box is better value per biscuit, but you will only eat half before they go stale. Is it still the better buy?
Step 4: Somewhere Else
Same thinking. Different situation.
Choosing a club
Two after-school clubs. One is $3 a session, pay as you go. The other is $20 for the term — ten sessions — but you can only make about five of them.
Which is better value?
Step 5: Quick Check
Two questions, then you are done.
Question 1 of 1
Two things cost the same. One is twice as big. Which is better value?
Step 6: Your Life Mission
Something to do away from the screen. Nobody is checking.
Find the better buy
- In a shop, find two sizes of the same thing.
- Work out the price for one unit of each.
- Say which is better value, and whether you would actually use it all.
Why: Doing it once in a real shop makes the shelf labels start to mean something.
Step 7: What You Learned
- Cheap and good value are different things.
- To compare, work out what one costs in each.
- Value you throw away was never value.
For the grown-up
Unit pricing is arithmetic the child already has by Grade 3, applied somewhere it pays. The obstacle is not the division; it is knowing that division is the thing to do.
Watch for "bigger is always better value" learned as a rule. It is usually true and it is not always true, and a child applying it to something perishable has learned a rule rather than a method.
The supermarket does this sum for you on the shelf label. Pointing at one is worth more than a worksheet.