## What you need to know

**Things to remember:**

- To turn a percentage into a decimal you have to divide by 100
- To turn a decimal into a percentage you have to multiply by 100.
- The best way to improve in this topic is practice multiplying and dividing by 100!

To start off with, let’s look at how we get from 100% to other percentages.

Percentage

100%

\div2 50%

\div4 25%

\div5 20%

\div10 10%

\div20 5%

\div50 2%

\div100 1%

But, we know that 100% represents a whole, or 100%=1, so we can use these same divisions to find some basic decimals.

Percentage Decimal

100% 1

\div2 50% 0.5

\div4 25% 0.25

\div5 20% 0.2

\div10 10% 0.1

\div20 5% 0.05

\div50 2% 0.02

\div100 1% 0.01

When comparing these percentages and decimals, it is important to notice that all that has actually happened is, we have divided by 100.

100\div100=1

50\div100=0.5

20\div100=0.2

5\div100=0.5

All we need to do is remember that when we divide by 100, we move all digits two places to the right.

77\%\div100 \rightarrow7.7\rightarrow0.77

77\%=0.77

123\%\div100 \rightarrow12.3\rightarrow1.23

123\%=1.23

3.1\%\div100 \rightarrow0.31\rightarrow0.031

3.1\%=0.31

How about if we want to go in the opposite direction and turn a decimal into a percentage? Well, we do the opposite, we multiply by 100!

*Hint:** Remember, when we multiply by 100, we move all the digits to the left two places.*

0.13\times100\rightarrow1.3\rightarrow13

0.13=13\%

1.67\times100\rightarrow16.7\rightarrow167

1.67=167\%

0.002\times100\rightarrow0.02\rightarrow0.2

0.002=0.2\%

## KS3 Maths Revision Cards

(63 Reviews) £8.99## Example Questions

**Question 1:** What is 37.6\% as a decimal?

37.6\%\div100 \rightarrow3.76\rightarrow0.376

37.6\%=0.376

**Question 2:** What is 2.34 as a percentage?

2.34\times100\rightarrow23.4\rightarrow234

2.34=234\%

## KS3 Maths Revision Cards

(63 Reviews) £8.99- All of the major KS2 Maths SATs topics covered
- Practice questions and answers on every topic

- Detailed model solutions for every question
- Suitable for students of all abilities.