Practise counting forwards and backwards to twenty.
Ask your grown-up to say a number between 2 and 19 and say the number that comes before, and the number that comes after.
Using a resource that you can find in your house, e.g. pencils or buttons or pasta pieces - count out 20.
From the amount, count out 12.
Now partition the 12 objects into 10 and 2 (a group of 10 and a group of 2).
This is partitioning using 10s and ones.
If you add 10 and 2 together, what is the total?
Try partitioning other numbers into 10s and ones (use a number that is more than 10 and less than 20).
You could write them as addition sentences - example 10 + 2 = 12