20’s
Math Concepts
Single-digit multiplication & Division
Materials
None
Players
2
Set up
Divide the class into pairs of students.
Play
In each pair, one person holds up some number of fingers from 2 to 10. After that, the other person holds up a number of fingers to multiply it by, and then says the product, which must be a number in the 20’s. At that point they switch roles.
For example, suppose the first person holds up 7 fingers. Then the second person has the choice of holding up 3 or 4 fingers. If they hold up 3 fingers, then they say 21 and they are done.
Goal
Take a quick break from other activities and have some fun doing multiplication and division.
Dicsussion and Tips
Discuss what the smallest possible starting number is for a given range of answers.
Talk about why sometimes there is more than one choice for how many fingers the second person can hold up.
Variations
Number Range
Use other ranges of numbers, such as 10’s, 30’s, 40’s, or 50’s. If the number range changes, you will need to adjust the lower limit for the first person. For example, if you use 40’s, the first person would need to pick a number from 4 to 10.