# Place value of decimals (tenths and hundredths)

## Learning focus

Learn how to write decimals using place value columns.

This lesson includes:

• one learning summary
• one interactive activity
• a quiz

# Quiz

Try the quiz below to find out how well you understand place value and decimals.

# Learn

### Decimals in daily life

Decimals are all around you:

• They are used to write amounts of money (£1.99).
• You see them when baking or on packets of food to show weight (1.5 kg of flour).
• They’re used in length (1.45 km).
• Even time uses decimals (10.15 seconds).

That is why it is important to understand how to write decimals and understand their place value.

## Tenths and hundredths

We use a decimal point to separate the whole from the parts of a whole.

• When one whole is divided into 10 parts, you call it a tenth.

• When one whole is divided into 100 parts, you call it a hundredth.

If you need a reminder, you can take a look at this lesson about tenths and hundredths.

The place value columns for tenths and hundredths look like this:

Let's look at how you write decimals.

## Example 1

How would you write thirteen and fifty-two hundredths as a decimal?

Use your knowledge of place value and partitioning. Thirteen is made up of one ten and three ones.

There are fifty-two hundredths. This is made up of 5 tenths and 2 hundredths. These numbers go after the decimal point.

So thirteen and fifty-two hundredths is written 13.52

## Example 2

Write $$\frac{21}{100}$$ as a decimal.

Use your knowledge of place value. $$\frac{21}{100}$$ (21 hundredths) is made up of 2 tenths and 1 hundredth.

In a place value chart that would look like this:

There are no ones, so you have to write zero in the ones column. This shows that it is a number smaller than one.

$$\frac{21}{100}$$ as a decimal is 0.21

# Practise

## Activity 1

Rearrange the numbers into the correct place value columns.