Sort the money and start with the notes or coins worth the most. Count on by each coin's value, changing the size of your jumps when the coins change. Dollars and cents are different units: $1 is 100 cents, and cents always take two places after the point. To make an amount with the fewest coins, use the largest coin that fits, then the next largest, until the amount is made.
Explore this idea with maths tools
Maths you can move
Build 8 + 5
Tap two gold counters to fill the ten-frame.
8 in the frame + 5 waiting. The total stays the same.
Words to know
- cents
- 100 cents make one dollar
- count on
- keep adding from the total so far
Worked examples
20c, 20c, 10c and 5c coins. How many cents are there altogether?
- 1.Start with the largest: 20, 40.
- 2.Count on: 50, 55.
= 55
A $5 note, a $2 coin and a 50c coin. How much money is there, in dollars?
- 1.Dollars first: $5, then $7.
- 2.Add the cents: $7.50.
= 7.5
What is the fewest number of coins that make exactly $3.70?
- 1.$2 + $1 makes $3, then 50c + 20c makes 70c.
- 2.That is 4 coins.
= 4
For parents
Method: Largest first, then count on
What to say: Which coin is worth the most? What is the total so far?
Common mistakes:
- Counts how many coins and notes there are instead of how much they are worth.
- Skip counts every coin by the first coin's value and doesn't switch when the coins change.
- Adds dollars and cents as if they were the same unit ($2 + 50c = 52c).
- Writes the cents in the wrong decimal place ($3 and 50c as $3.05, or $3 and 5c as $3.5).
- Makes the amount without using the largest coins ($2 and 50c), so uses more coins than needed.
- Uses $1 coins for the dollars and forgets that $2 coins exist.
- Counts only the coins for the cents and forgets the dollars.