Here we have a straightforward maths worksheet on knowing pairs of numbers that add up to twenty. This is suitable for year 2 children or those who are already very confident with knowing pairs of numbers that make ten.
If these facts are not known there are several ways of working the answers out, including:
1. Counting on from the smaller number.
2. Counting on from the smaller number up to 10 and then adding another 10. (If smaller number is below 10.)
3. Counting back from 20, which is trickier.
A good follow up to this page is to ask how many different ways you can make 20 by adding just two numbers.
If you are looking for resources for Key Stage 1, then urbrainy.com is well worth a visit.