ACARA v9 CONTENT DESCRIPTION “identify the relationships between dollars and cents; estimate, count and solve simple problems with money in everyday contexts”
Money is a measurement children meet every day, and this unit is about handling it practically: knowing the relationship between dollars and cents, counting a collection of coins, estimating what a few things will cost, and solving simple money problems. A dollar is one hundred cents, so money works as two units together, and counting coins is just adding their values. Because money is so concrete — real coins in a real hand — it is one of the most useful and motivating contexts for the number skills Year 3 has been building all year.
A dollar in coins
One dollar is one hundred cents, and coins can make it in several ways.
One dollar is 100 cents. Each of these coin sets adds up to exactly one dollar.
Dollars and cents
The relationship at the centre of money is that one dollar equals one hundred cents. This makes dollars and cents a two-unit system, with cents the smaller unit and dollars the larger, exactly a hundred to one. The same dollar can be made from many different coin sets — a single dollar coin, two fifties, or five twenties — and seeing those equal totals builds a feel for the value. Knowing how dollars and cents relate is what lets a child move between counting cents and naming an amount in dollars.
Count the coins
To find how much a handful of coins is worth, add the coins together.
Reveal and add the coins one at a time to find the total.
Counting a handful of coins
To find how much a handful of coins is worth, you count them up — and counting from the largest coin down keeps it manageable. A dollar, then fifty, then twenty, then ten builds to a running total of $1.80. This is addition with the values of real coins, the same skill from the Number strand applied to what is in a purse. Counting money carefully matters in a way few classroom sums do, because the total is real, and a child who can count coins can check their own change at a shop.
Skip count one coin
A pile of one kind of coin is counted by skip-counting in that coin's value.
Counting 20c coins: 20. Same-value coins are counted by skip-counting.
Counting coins of one kind
When the coins are all the same, counting them is skip-counting in that coin's value: four twenty-cent coins are 20, 40, 60, 80 cents, and three fifties are 50, 100, 150. This is exactly the skip-counting and times-table work from earlier units, now with money. It is a fast, reliable way to count a pile of identical coins, and it shows why knowing the times tables pays off in real life. Counting coins of one kind is often the quickest first step before adding the rest of a mixed handful.
Dollars and cents
A total in cents can be written in dollars and cents, two ways of the one amount.
How is 170 cents written as dollars and cents?
Writing it two ways
A coin total can be written in cents or in dollars and cents: 170 cents is also $1.70, and 80 cents is $0.80. The two digits after the point are always the cents, so eighty cents is $0.80 and five cents is $0.05, never $0.8 or $0.5. Being able to write an amount both ways, and to read a price in dollars and cents, is part of identifying the dollar-cent relationship. Prices in shops are written in dollars and cents, so reading that form fluently is an everyday necessity.
Estimate the total
Estimating a money total means rounding each price to the nearest dollar, then adding.
Estimate the total by rounding each price to the nearest dollar, then adding.
Estimating a total
Often an exact total is not needed, just a rough idea, and estimating is the skill for that: round each price to the nearest dollar and add the rounded amounts. Prices of 95c, $2.10 and $1.40 round to $1, $2 and $1, giving about $4 — close to the actual $4.45. Estimating money, named directly in the descriptor, is genuinely useful at a shop, where a quick estimate tells you roughly what you will pay and whether you have enough, without adding every cent.
Enough money?
A simple money problem checks whether you have enough, and what is left over.
You have $5.00 and it costs $3.80. Is that enough?
Solving a money problem
The skills come together in simple everyday problems: do I have enough, and how much is left? If you have $5 and something costs $3.80, comparing the two shows you can afford it, and subtracting tells you $1.20 is left over. These are the small money decisions of real life, solved with the comparing and subtracting Year 3 has practised. Solving simple money problems in everyday contexts, exactly as the descriptor asks, is the practical payoff of the whole unit. With the dollar-cent relationship, coin counting, estimating and simple problems all in hand, a child can handle everyday money — and the Year 3 Measurement strand is complete.
Quick self-check
1. How many cents are in one dollar?
2. You have a $1 coin, a 50c coin and a 20c coin. How much is that?
3. About how much is 95c + $2.10 + $1.40, to the nearest dollar?