You can use number lines like the one below to help you learn how to count on and count back. Test out your knowledge of counting on to and back from 20 with this quiz, then read on to complete ...

Counting groups is a good way of understanding division. Here are 15 beads. How many groups of 5 can you make with these beads? When you divide 15 into groups of 5, you make 3 groups. A number ...