For 6 minutes, increase by 1 rep each round. See how high your child can get in the time limit.
1 mountain climber
1 Addition question
2 mountain climbers
2 Addition questions
3 mountain climbers
3 addition questions
And so on, for 10:00. Adjust time limit as needed.
Substitute any quick mental math operation (addition, subtraction, multiplication or division) based on age and ability level.
Google Images is the easiest place to find basic free pintables.