Serve a ‘number’ under 100. Your partner must return the serve by responding with the number that would make your total 100, within a strict 5 second time limit. e.g. 1) serve “45” 2) responds “55”. Variations: 20, 1000
Give your partner a start number and ask them to count backwards or forwards. They must say the next 5 numbers in the sequence. If the manage it they get a ‘high 5’. You can make it more challenging by varying the jumps .e.g. count backwards from 55 in 6s.
Think of a number and keep it to yourself. Your partner will then ask questions to work out what it is. e.g. “Is it an even number?”, “Is it a multiple of 5?”
Come up with ‘crazy problems’ together and then try to solve them! e.g. How old am I … in days?