How can I use adding and subtracting to work out change?

Pounds and pence

Money comes in pounds and pence. One pound is the same as 100 pence.

Pounds are written with a £ before the number:

  • for example two pounds is written as £2.

Pence are written with a p after the number:

  • for example twenty pence is written as 20p

Sometimes pounds and pence are written together as £ then the number of pounds then a dot then the number of pence.

  • for example one pound and fifty pence is written as £1.50

How do you add and subtract money?

If you are just working with pounds, or just working with pence, you can add and subtract just like with ordinary numbers.

If you are working with pounds and pence, remember that 100p=£1

Bridging through 100 can help. Here's what to do:

  • work out what you need to add to your first number of pence to make 100

  • add 1 to the pounds for the 100 pence

  • subtract what you added from the second number

  • the number you have left says how many pence you have

  • add this to the number of pounds you have for the final answer


What is 70p + 40p?

What do you need to add to 70p to make 100p?

70p + 30p = 100p

This makes £1.

Take 30p away from 40p

40p - 30p = 10p

Add this to the pounds to make £1.10p