you start at 20 and count back until you reach 1 (or zero). Each number is one less than the last. You can use number lines like the one below to help you learn how to count on and count back.

Numbers to 20 Learn on how to count on and back from 0 to 20. Compare and order numbers within 20 Find out how to order the numbers 1 - 20, using strawberries, books and numbers.