Counting is easy to build into your day as it can happen anytime and anywhere. We can count items like raisins for a snack, cutlery when setting the table, books read and toys such as cars and teddies. We can also count actions likes jumps or claps. Maybe you could challenge your child to do something like tidying up their toys and count how many seconds it takes them to do this.
Counting songs are a great way of engaging young children in counting and the concept of adding and taking away. There are some examples on these on this bbc website. https://www.bbc.co.uk/teach/school-radio/nursery-rhymes-counting-songs/zn67kmn. Could you make some simple puppets to act out these songs.
https://www.topmarks.co.uk/maths-games/3-5-years/counting There are lots of maths games online to practise counting, ordering numbers and sorting objects by shape and size. Many of the games are tablet friendly.
Traditional games such as Dominos, Snakes and Ladders and hopscotch are also a fun way of supporting developing maths skills.