Continue playing games involving number. If your child is secure with numbers to 20 you can play some of the following games, but asking 1 more or 1 less questions, or incorporating addition and subtraction.
At bath time have a variety of different size and shape containers. Which will hold the most water? How do you know? Test your ideas. Can you order the containers by how much water they hold?
Can you hide a toy and then direct an adult to find it? Can you use words such as 'forwards', 'backwards', 'to the side', 'side step', 'turn', 'left' and 'right' to help guide them to the toy? How many steps do you think they might been to take?
Estimating is taking a good guess at how much or how many there may be. Fill a container with some buttons, pennies, twigs or another object you have lots of. You can start with less at first. How many do you think are in the container? Count them out. How close were you? Try again with a different amount.