You will need:
bowling pins - empty plastic bottle, plastic cups, toilet roll tubes (anything that can stand up and be knocked over)
ball - a rolled up pair of socks will work
Set up a bowling activity using up to 5 items.
Take turns to bowl. Each time you roll the ball, can you sort, or partition, the items that are left standing and those that fall over - these are your two parts.
How many do you start with?
How many have fallen over?
How many are still standing?