What is a decimal number?
A decimal number is a number with a decimal point, like 3.25 (a price, a length…). The decimal point separates two parts:
- on the left, the whole part (units, tens, hundreds…);
- on the right, the decimal part: the tenths, the hundredths, the thousandths.
The place-value table
The table puts each digit in its place. Example with 12.45:
| Tens | Units | Tenths | Hundredths | |
|---|---|---|---|---|
| 1 | 2 | . | 4 | 5 |
12.45 = 1 ten, 2 units, 4 tenths and 5 hundredths
You read: "twelve point four five", or "twelve units and forty-five hundredths".
Reading a decimal number
The first digit after the point is the tenths; the second, the hundredths; the third, the thousandths. In 0.7, the 7 is a tenths digit → "seven tenths". In 0.07, the 7 is in the hundredths → "seven hundredths", which is ten times smaller.
Comparing and ordering decimals
To compare two decimal numbers:
- First compare the whole part. The larger one wins.
- If they are equal, compare the tenths, then the hundredths, digit by digit.
Example: 3.5 and 3.45. Whole parts equal (3). Tenths: 5 > 4, so 3.5 > 3.45.
Decimals and fractions
A decimal number is another way of writing a decimal fraction: 0.1 = 110, and 0.25 = 25100 = 14. That's why decimals are taught right after fractions.
Worked exercises
What is the hundredths digit in 7.86?
Put in increasing order: 2.4 — 2.04 — 2.40
Write "three units and six tenths" in figures
True or false: 5.9 < 5.12?
Now it's your turn!
On EasyMaths, your child practises decimal numbers with varied exercises and instant marking. The first exercises are free.
Start the exercises →Frequently asked questions
What is a decimal number?
A decimal number is a number with a decimal point. To the left of the point is the whole part, to the right the decimal part: the tenths, hundredths and thousandths.
How do you compare two decimal numbers?
First compare the whole parts. If they are equal, compare the tenths, then the hundredths, digit by digit. Careful: 3.5 is greater than 3.45.
Can you add zeros after the decimal point?
Yes, a zero at the end of the decimal part does not change the value: 3.5 = 3.50 = 3.500. It helps compare by lining up the number of decimal places.