Primary 5 · Number & Algebra

P5 decimals

In P5, your child multiplies and divides decimals by 10, 100 and 1000, and by multiples such as 40 or 700. They also write measurements in decimals, so 3 m 8 cm becomes 3.08 m. Most lost marks come from a missing step, not hard arithmetic.

Taught in: Term 3
Syllabus: 2 skills
Usual slip: Divides by 4 only

Updated 13 October 2026

Place-value chart showing 4.7 divided by 100 is 0.047

What your child learns in P5 decimals

Two skills, each with what it looks like on a worksheet.

Follows the latest (2026) MOE syllabus

See the syllabus wording

multiplying and dividing decimals (up to 3 decimal places) by 10, 100, 1000 and their multiples without calculator
converting a measurement from a smaller unit to a larger unit in decimal form, and vice versa: kilometres and metres, metres and centimetres, kilograms and grams, litres and millilitres

By 10, 100, 1000 and their multiples

Multiplying by 10, 100 or 1000 moves each digit one, two or three places left. Dividing moves them right, so 4.7 ÷ 100 = 0.047. A multiple such as 300 takes two steps: × 3, then × 100.

Ones	Tenths	Hundredths	Thousandths
4	7
0	0	4	7

4.7 ÷ 100 = 0.047

Measurements in decimals

1 m is 100 cm, so 1 cm is one hundredth of a metre and 2 m 5 cm is 2.05 m, not 2.5 m. A km, a kg and a litre are each 1000 of the smaller unit.

Measurement	As a decimal
2 m 5 cm	2.05 m
3 kg 40 g	3.04 kg
1 km 250 m	1.25 km
850 mℓ	0.85 ℓ

Each measurement in the larger unit

Key facts and formulas

Term 3 · revision

Hundreds Tens Ones . Tenths Hundredths Thousandths
2.375 2 . 3 7 5
× 100 2 3 7 . 5
× or ÷ by 10, 100, 1000× moves every digit 1, 2 or 3 places left. ÷ moves them right. $2.375 \times 100 =$ $237.5$ $46.2 \div 100 =$ $0.462$ $0.35 \times 60 =$ $0.35 \times 6 \times 10 =$ $21$
cm
4500
÷ 100
m
45
÷ 1000
km
0.045
Changing unitsTo a bigger unit, ÷. To a smaller unit, ×.4500 cm → $4500 \div 100 =$ $45\,\text{m}$

	Hundreds	Tens	Ones	.	Tenths	Hundredths	Thousandths
2.375			2	.	3	7	5
× 100	2	3	7	.	5

Words to know

Place value: What a digit is worth because of its place. In 0.047, the 4 is 4 hundredths.
Place-value chart: Columns for ones, tenths, hundredths and thousandths, with one digit in each column.
Thousandths: The third place after the decimal point. 0.007 is 7 thousandths.
Multiple of 100: A number such as 300 or 700, which is a 1-digit number times 100.

The sentence that costs the mark

Find the value of 8.4 ÷ 400.

8.4

÷ 4

2.1

÷ 100

0.021

400 is 4 × 100, so 8.4 ÷ 400 takes two steps

What the working usually does

only ÷ 48.4=2.1

Splits 400 into 4 × 100, divides by 4 and stops. The answer is a neat decimal, so the working looks finished.

What the question asked

÷ 4, then ÷ 1008.4=0.021

Divides by 4, then by 100, because 400 is 4 hundreds. Each digit moves two places to the right.

The first division is correct in both columns. The slip is stopping there. If 400 people share 8.4 litres, each person gets far less than 1 litre, so 2.1 cannot be right.

The same P5 decimals question, worked properly

Lah works through it the way she does every question in StudyLah: one step at a time, marking the picture as she goes.

Raj had 47.6 ℓ of lemonade and poured it equally into 700 cups. How many litres of lemonade did each cup contain?

Step 1 of 5▌

The lemonade is shared equally, so divide the total by the number of cups. 700 is 7 × 100, so we divide in two steps.
Divide by 7 first: 47.6 ÷ 7 = 6.8.
6.8 is only 47.6 ÷ 7, so it is not the answer yet. Divide by 100 too. In place value, each digit moves two places to the right: 6.8 ÷ 100 = 0.068.
700 cups share 47.6 ℓ, so each cup gets far less than 1 litre. 0.068 ℓ fits. 6.8 ℓ is far too much for one cup.
So each cup held 0.068 ℓ.

Every question in StudyLah comes with a walkthrough like this one.

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Three quick P5 decimals questions

Try them together, then tap to check.

Question 1

Divide 9.6 by 60.

Show answer

Answer0.16. Split 60 into 6 × 10. 9.6 ÷ 6 = 1.6, then 1.6 ÷ 10 = 0.16.

Question 2

Each glass bead has a mass of 25.5 g. Find the total mass of 80 such beads, in kilograms.

Show answer

Answer2.04 kg. 25.5 × 8 = 204, then 204 × 10 = 2040 g. 2040 g ÷ 1000 = 2.04 kg.

Question 3

Express $2\frac{3}{4}$ as a decimal.

Show answer

Answer2.75. The whole number 2 stays, and $\frac{3}{4}$ = $\frac{75}{100}$ , which is 0.75.

Helping at home

How to tell it has clicked

You do not need to do the division yourself. Ask one question first: will each share be more than 1 or less than 1? If 400 people share 8.4 litres, it has to be much less.

Then look at the working. If it stops after ÷ 4, the ÷ 100 is missing. Every multiple of 100 needs that second step, and it is the one that gets dropped.

Try this tonight

Use money. Sharing $8.40 among 4 people gives $2.10 each. Shared among 400 people, each gets about 2 cents.

Ask why the two answers are so far apart. 400 is a hundred times 4, so each share is a hundred times smaller. That is the ÷ 100 step in words.

Before and after P5 decimals

Builds on
Primary 4 Decimals
Compares decimals place by place
You are here
Primary 5 Decimals
Moves decimals by 10, 100 and 1000

More in Primary 5

Struggling with the working rather than the topic itself? How to help your child with problem sums

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.

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