An abacus is an excellent resource for helping your child understand 2-digit numbers up to 99. It shows clearly the two columns, the ones and the tens. In other words the 2 yellow balls in the tens column have a value of 20 whilst the two balls in the ones column have a value of 2. This will also help later when multiplying by 10 as they can see each digit moving one place to the left.

Fill in the missing numbers in these part-whole models.

Using base 10 blocks with 2-digit numbers.

Show the numbers represented by the base 10 images.