Put small characters such as dinosaurs or toy animals in a group. Can you use kitchen tongs to pick them up and move them into a line (this will make it easier to count them)? How many are there in the line? Repeat this activity with different numbers of characters.
Use your 1-20 number cards and turn them face down on the table. Turn over three cards, can you put them in order? Which is the smallest number and which is the biggest?
Can you make some number snakes? Cut out some long strips of paper. Can you write numbers 1-20 on them in the right order?
Collect some leaves and let's make a number necklace! Write a number on each leaf and see if you can thread them in order onto some string to make your own necklace.