Primary 1 · Mathematics
P1 money
Four coins against one, so the four must be more money? Not when the one is a 50-cent coin. A handful of real coins settles it faster than any worksheet.
- Level
- P1
- Usually taught
- Term 4
- Covers
- 1 concept
What changes at P1
Primary 1 learns Singapore coins and notes. Your child counts cents up to $1 and dollars up to $100 and finds how much a set is worth. They also work out what can be bought, and what is left.
Many children handle less cash than their parents did, so the coins themselves are less familiar. Counting by value, starting with the largest coin, is the skill the papers test.
The sentence that costs the mark
Set A has four 10¢ coins. Set B has one 50¢ coin. Which set has more money?
What the working usually does
which has more?count the coins=Set A
Counts 4 coins against 1 coin, and 4 is more.
What the question asked
which has more?count the value=Set B
Counts 40¢ against 50¢, and 50¢ is more.
The coins were counted accurately, and 4 really is more than 1. The wrong thing was counted: how many coins, not what each one is worth. With fewer coins in everyday life, there is less to correct it.
| Group | Detail |
|---|---|
| Set A | 4×10c |
| Set B | 1×50c |
The same question, worked properly
Count Set A by value
10¢, 20¢, 30¢, 40¢Four 10-cent coins. Count on in tens, one coin at a time: Set A has 40¢.
Count Set B by value
one 50¢ coin = 50¢This is the step that fails. Only one coin, but it is worth 50 cents. One coin can be worth more than several, which is the step a coin count skips.
Compare the values
50¢ > 40¢, so Set B50¢ is more than 40¢, so Set B has more money, even though it has fewer coins.
How can you tell it has clicked?
Put four 10-cent coins beside one 50-cent coin and ask which has more money. Picking the pile of four means the coins are being counted, not their value.
Next, count the value aloud together: 10, 20, 30, 40, and 50 for the single coin. A child who starts with the largest coin and counts on by its value has it.
One thing to try tonight
Put four 10-cent coins in one hand and a 50-cent coin in the other, and ask which hand could buy more.
Then count the value of each hand aloud together. Real coins work better than any worksheet, and paying at a hawker stall gives plenty of practice.
What your child will meet in this topic
- Money
Most Singapore schools introduce this in Term 4, though schools do differ by a term either way. If your child’s school runs a different order, you can set it in the schedule on your dashboard.
What it leads to
In P2, money is written with a decimal point ($1.35) and changed between dollars and cents. Counting by value, largest first, carries straight over.
The P1 papers already add a second step: having $85, buying one thing and then another, and finding what is left. Each step starts with knowing what an amount is worth, which is why counting by value comes first.
More in Primary 1
Other topics in the same year, so you can see what sits either side of this one.
See how your child is doing on this topic
StudyLah marks each step separately, so you can see whether it was the setup or the arithmetic that cost the mark.