Try to learn to tell the time. You could make a clock together with moving hands. In Year 1, children need to tell the time to the hour and half past the hour – but of course there is no barrier to their learning if they are able to go beyond this.
Make a number line to 50 or 100 number square. Take it in turns to throw a dice and move on that number or squares. First to the end is the winner. Start from 0 or from 50 and count back.
Make single digit number cards 0-9. Turn them blank side up. Take it in turns to choose 2 to make a 2 digit number eg 3 and 4 to make 34. Whoever makes the highest number wins a counter, first to get 10 counters is the winner.
Practise counting forwards and backwards in 2s, 5s and 10s. March around the garden reciting the times tables.
https://www.topmarks.co.uk/- a large collection of maths games.
Play simple board games to help with counting on and back, anticipating how many are needed to finish.
Play card games, snap, higher/lower, pairs etc