P1 Money: Count Coins in Cents and Notes in Dollars

An empty glass jar waits on the screen, with coins and a note floating above it. "Coins and notes! Let's count the money in the jar." One by one, the money drops in, and the total counts on underneath.

That is Penny Jar, a 30-second Primary 1 episode of our Topic Explainers series. It is made for your child to watch, with simple words on screen and no voice-over. Watch it together first, then read on.

Penny Jar: count coins, count notes, fill the jar!

The jar fills in three rounds. First, four coins drop in and the total counts 5, 25, 35, 55 cents. Next, ten 10-cent coins drop in and the total counts from 10 cents all the way to 100 cents, and then a one-dollar coin pops in: 100 cents is one dollar. Last, notes drop in and the total counts in dollars: 2, 7, 17, 27 dollars.

In Primary 1, the MOE syllabus asks children to count an amount of money in cents up to one dollar, and in dollars up to 100 dollars. Penny Jar covers both, and the moment where they meet.

The method

Counting money needs two ideas that are new to most six-year-olds.

1. Count the value, not the coins. Four coins are not "4". A 20-cent coin counts as 20, and a 10-dollar note counts as 10. Each object stands for a number written on it.

2. Keep the unit. Coins are counted in cents and notes are counted in dollars, and the unit is part of the answer. "55" is not finished; "55 cents" is. The penny jar shows a total of 55 cents and, later, a total of 27 dollars, and those are very different amounts of money even though both are numbers under 100.

The way to count is the same for coins and for notes: start with the first value, then count on as each new one arrives, saying the running total aloud. Once the counting is comfortable, there is one more idea to meet: 100 cents make 1 dollar.

In Singapore, children see coins of 5, 10, 20 and 50 cents and a one-dollar coin, and notes of 2, 5, 10, 50 and 100 dollars. At P1, the amounts stay at or below one dollar for cents and at or below 100 dollars for notes, with no decimal point.

Worked examples

Worked example 1: count the coins as they drop

The coins drop into the jar in this order: 5 cents, 20 cents, 10 cents, 20 cents. How much is in the jar?

Step 1: Start with the first coin. The first coin is worth 5 cents. The total is 5 cents.

Step 2: Count on with each new coin.

Coin that drops in	What to think	Total in the jar
5 cents	start here	5 cents
20 cents	`5 + 20 = 25`	25 cents
10 cents	`25 + 10 = 35`	35 cents
20 cents	`35 + 20 = 55`	55 cents

Step 3: Say the answer with its unit. There are 55 cents in the jar.

Step 4: Check another way. Our post on counting coins and number sense shows a useful habit: sort the coins and start with the biggest. Here that gives 20, 40, 50, 55 cents. Same answer. Counting in the order the coins arrive is useful too, because money often comes one coin at a time, like coins dropping into a jar or a shopkeeper's change.

Worked example 2: 100 cents make 1 dollar

Next, ten 10-cent coins drop in, one at a time.

Step 1: Count on in tens. 10, 20, 30, 40, 50, 60, 70, 80, 90, 100. There are 100 cents.

Step 2: Swap for a dollar. 100 cents is the same amount of money as one dollar. So the ten small coins can be swapped for a single one-dollar coin, and the amount does not change.

This is the moment many children find surprising. Ten coins are worth the same as one coin. It is the same idea as ten ones making one ten in place value, and it is why we count cents only up to 100 at this level: at 100 cents, the money has become a dollar.

Two quick questions help it sink in:

"How many 10-cent coins make one dollar?" (10)
"How many 50-cent coins make one dollar?" (2, because 50 cents and 50 cents make 100 cents)

Worked example 3: count the notes

Now the notes drop in: a 2-dollar note, a 5-dollar note, a 10-dollar note and another 10-dollar note. How much is in the jar?

Step 1: Start with the first note. The total is 2 dollars.

Step 2: Count on with each new note.

Note that drops in	What to think	Total in the jar
2 dollars	start here	2 dollars
5 dollars	`2 + 5 = 7`	7 dollars
10 dollars	`7 + 10 = 17`	17 dollars
10 dollars	`17 + 10 = 27`	27 dollars

Step 3: Say the answer with its unit. There are 27 dollars in notes, written $27.

Notice that adding a 10-dollar note only changes the tens digit: 7 becomes 17, and 17 becomes 27. That is a lovely pattern to point out, because it shows your child that counting on by ten is a small, friendly step.

Common mistakes

Counting the coins, not the value. "There are four coins, so it's 4 cents." Before counting, ask, "What is this coin worth?"
Mixing up cents and dollars. A 20-cent coin and a 2-dollar note both show the digit 2, but they are very different amounts. Ask, "Is this a coin or a note? Cents or dollars?"
Starting again from zero. After each coin or note, some children recount everything from the beginning. Encourage your child to say the running total aloud and carry on from it.
Thinking more coins means more money. Ten 10-cent coins look like a lot more than one one-dollar coin, yet they are worth the same. Lay them side by side and talk about it.
Dropping the unit. "55" should be "55 cents", and "27" should be "27 dollars".

Parent tips

Make your own penny jar. Use a clear jar or cup. Drop in three or four coins one at a time while your child says the total aloud after each one. Then tip them out and count again, biggest coin first, to check.
The ten-coin swap. Count out ten 10-cent coins with your child, then swap them for a one-dollar coin. Try two 50-cent coins, or five 20-cent coins, and see that each set makes one dollar too.
Play shop with notes. Use play notes, or draw your own. Give your child a few notes and ask them to count how many dollars they have, keeping every total at or below 100 dollars.
Coin or note? Mix a few coins and notes on the table. Your child sorts them into a cents pile and a dollars pile before counting either one.
Say the unit every time. Make it a family rule: every money answer ends with "cents" or "dollars".

Keep each game to a few minutes and stop while it is still fun. Real coins and notes come first, then pictures of money, then written numbers. That is the concrete, pictorial, abstract order of Singapore math teaching. For more Primary 1 examples, Primary 1 sample questions explained walks through a money question step by step, and our P1 math readiness checklist shows where money sits in the year.

Calm practice, a few questions at a time

Money is one of the first topics where a P1 child uses several number skills at once: reading a value, counting on, and holding a running total. Like everything else at this age, it settles in through short, happy practice, not long sessions.

That is how we built Singapore Math Drills. Practice is calm by design: no guilt-tripping over a missed day and no dark patterns, and your child's progress is only ever measured against their own. Our free sample has real practice questions for every Primary level, with no login and no download. Count coins. Count notes. Fill the jar!

Try a sample

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

Try a free Singapore math sample