Counting forwards to 20
By the end of Reception, children are expected to be able to count forwards and backwards to 20.
Here's a link to a fun way (with a little bit of movement too!) to sing along and count to 20 forwards.
Counting backwards from 20
Here is a link to help with practising counting backwards from 20.
Why do you notice about the ending of the words from nineteen to thirteen? (teen)