Why Counting Coins Builds Number Sense in P1 Maths

Live from a bedroom, it's prime time on zero budget. The Mastermind, in a hairband headset with a desk lamp for a studio light, is selling the Practice-O-Matic: a cardboard box with a bow. "But wait, there's MORE!" Every "more" turns out to be the next question card. His only viewer, the Partner, sits on the bed with a juice box and is not impressed. "You're selling me five questions."

That is But Wait, There's More, the second episode of our comedy series, The Mastermind. Watch it first (it is under a minute), then read on. The best part of the deal is inside the box.

But Wait, There's More: five a day. Nobody has to know.

When the box finally opens, there is a piggy bank and one question: how much money is in the piggy bank? Four coins drop out, a 50-cent coin, two 20-cent coins and a 5-cent coin, and they are counted on: 50 cents, 70 cents, 90 cents, 95 cents. The prize, it turns out, is the counting, not the money.

Counting coins is counting on

In Primary 1, children learn to count an amount of money in cents, up to one dollar. It looks like a small, practical topic. In fact it is one of the first places a child uses several number skills at the same time.

To count a handful of coins, your child has to:

Read the value, not the number of coins. Four coins are not "4". A 50-cent coin is worth more than two 20-cent coins put together. For many children this is the first time one object stands for many.
Count on from a number other than 0 or 1. Starting at 50 and adding 20 means thinking "50 ... 70", not counting from the beginning again.
Count in steps. Tens, twenties and fives. Saying "50, 70, 90" is skip counting in 20s, a pattern children meet again when they learn multiplication.
Hold a running total in mind. Each new coin changes the total, and your child has to remember where they are.

Together, these are the habits that make up number sense: knowing roughly how big a number is, seeing how numbers relate to each other, and moving between them flexibly. Coins give your child something real to hold while they practise all of it.

Start with the biggest coin

The piggy bank in the episode shows the most useful coin-counting habit of all: sort the coins, then start with the biggest one.

Worked example: the piggy bank

The coins are one 50-cent coin, two 20-cent coins and one 5-cent coin. How much money is there altogether?

Step 1: Sort the coins. Line them up from the biggest value to the smallest: 50 cents, 20 cents, 20 cents, 5 cents.

Step 2: Start with the first coin's value. Start at 50 cents. There is no need to count up to 50, because the coin already tells you.

Step 3: Count on, one coin at a time.

Coin added	What to think	Running total
50-cent coin	Start here	50 cents
20-cent coin	`50 + 20 = 70`	70 cents
20-cent coin	`70 + 20 = 90`	90 cents
5-cent coin	`90 + 5 = 95`	95 cents

Step 4: Say the answer with its unit. There are 95 cents in the piggy bank.

Step 5: Check. Count again in a different order. The two 20-cent coins make 40 cents, the 50-cent coin takes the total to 90 cents, and the 5-cent coin makes 95 cents. Same answer. You can also ask, "Is it more or less than one dollar?" One dollar is 100 cents, so 95 cents is 5 cents less than a dollar.

Why the biggest coin goes first

Try the same coins smallest first: 5, then 25, then 45, then add 50 to make 95. That last step, adding 50 to 45, is a big jump for a six- or seven-year-old. Starting with the biggest coin keeps every step small and friendly: add 20 to a round number, add 20 again, then add 5 at the end.

Look out for three common slips:

Counting coins instead of value. "There are four coins, so it's 4 cents." Ask, "What is this coin worth?" before counting.
Starting again from zero after each coin. Encourage your child to say the running total aloud and keep going from it.
Leaving out the unit. "95" becomes "95 cents". Saying the unit every time keeps the meaning attached to the number.

A simple fix for the first two: let your child touch or slide each coin across as it is counted, saying the new total each time. Moving the coin and saying the number together keeps the count in order.

Five ways to practise with real coins at home

You do not need worksheets for this. The coins in your wallet are enough. For Primary 1, keep each total at or below one dollar (100 cents) and use the coins children see every day: 5 cents, 10 cents, 20 cents and 50 cents.

The piggy bank count. Put three or four coins in a cup. Your child tips them out, sorts them from biggest to smallest, and counts on aloud. Then swap roles: you count, and make one deliberate slip ("50, 60 ...") for your child to catch.
Sort before you count. Give your child a small pile of mixed coins and ask them to group the coins by value before adding anything. Talking about which coin is "worth the most" builds the idea of value first.
Skip-counting trains. Lay out a line of the same coin: five 10-cent coins (10, 20, 30, 40, 50) or four 20-cent coins (20, 40, 60, 80). Your child touches each coin and says the total. Then add a 5-cent coin to the end of the train and count on once more.
Make the amount. Name an amount, such as 35 cents, and ask your child to make it with coins. There is often more than one way: a 20-cent coin, a 10-cent coin and a 5-cent coin, or three 10-cent coins and a 5-cent coin. Finding two ways is a lovely conversation about why both work.
How much more to make one dollar? Count a small set together, say 70 cents. Then ask how much more is needed to make 100 cents. Counting on in tens, 80, 90, 100, gives 30 cents.

A few small habits make these games work:

Keep it short. Five minutes and a handful of coins is plenty. Stop while your child still wants to play.
Real coins first, then pictures, then numbers. Holding and moving coins comes before counting coins in a picture, and pictures come before written sums. This is the concrete, pictorial, abstract order that Singapore math teaching follows.
Ask before you tell. When your child gets stuck, try "Which coin is worth the most?" or "Where are we now?" before showing the next step.

If you would like more Primary 1 money examples, our guide to Primary 1 sample questions explained walks through another coins question step by step.

Five calm questions a day

The joke in the episode is that the "amazing new product" is just five questions a day. We think that is the best part of the deal. A short coin count at the kitchen table, and a small set of questions on most days, give your child many low-pressure chances to use the same few skills until they feel familiar.

That is the idea we built Singapore Math Drills around:

Daily Five drills: five hand-picked drill cards are waiting each day, so your child never has to decide what to practise.
Calm by design: no guilt-tripping over a missed streak and no dark patterns. Your child's progress is only ever measured against their own.

Five calm questions a day, and a missed day is simply a missed day. If you would like to know why little and often works, our post on why five a day works goes deeper, with Episode 1 of The Mastermind, The Heist.

Five a day. Nobody has to know.

Try it free

Try a free interactive Primary 1 worksheet and see how calm practice feels, with no signup or credit card required.

Try the free Primary 1 sample worksheet