Jo has used this task with a lot of success on the first days of school with very hesitant students. Soon after setting the challenge the board area becomes full of students putting up their solutions, then returning to their seat to look for more. For students, it is a very safe and non threatening activity. It builds number sense and is a fun challenge. This task is also a really nice way of helping students become comfortable sharing their work in front of the class. The first appearance of four 4’s was in English mathematician: WW Rouse Ball’s Mathematical Recreations and Essays in 1892, and then revisited by Constance Reid in ‘From Zero to Infinity’ in 1955.
Task Instructions
Can you find every number between 1 and 20 using only four 4’s and any operation?
or
Can we as a class find every number between 1 and 20 using only four 4’s and any operation?
Here’s an example √4 + √4 + 4⁄4 =
Give this challenge to students and write all the numbers from 1 to 20 on the board. Then ask students to come to the board and write a solution any time they have one. The more solutions you get for each number the better.