Our new Year 3 resources concentrate on finding complements to 100. This means, working out the number that needs to be added to another number to make a total of 100.

A common error when doing this is to add the ones digits to make 10 and then add the tens digits to make 100, leading to a total of 110. e.g. 25 + 85.

There are two, equally good, ways of quickly reaching the correct answer. If we look at what number needs to be added to 36 to make 100:

Method 1: add 60 to 36 to make 96 and then add, or count on 4, to make 100. Answer: 64.

Method 2: add 4 to the 36 to make 40 and then add 60 to make 100. Answer: 64.

This is a very important skill, especially helpful when working out change from £1.

Why not take a look at our latest addition worksheets now.