We use number all the time, practise counting, recognition and writing numbers to 20. There are lots of fabulous interactive games online you can use.
We have been doing doubling and halving this week, you could practise this with fruit (cutting an apple in half). Give you child a number and ask them to double it using any counting blocks/lego you have at home.
Last week we where looking at tens and ones. Knowing that 12 is 1 ten and 2 ones.