Page 28 - NUMINO Challenge_B1

Basic Concepts Four Fours

Four Fours is a math puzzle in which you can form equations with answer
from 1 to 100, using four 4’s and various operation symbols ( , , , ).
Using four 4’s, operation symbols ( , , , ), and parentheses, we can
form the following equations:

4 4 44 1 (4 4) 4 4 4 44 4 4 7

4 4 (4 4) 2 (4 4 4) 4 5 44448

(4 4 4) 4 3 4 (4 4) 4 6 44449

Example Use five 3’s, operation symbols ( , , , ), and parentheses to
make the following equations true.

33333 1
33333 2
33333 3
33333 4
33333 5

Class Notes

Since 3 3 1, you can use two 1’s and a 3 to make the following equations true.

3 1 11 3 (3 3) (3 3) 1
3 1 12 3 (3 3) (3 3) 2
3 1 13 3 (3 3) (3 3) 3

3 1 14 3 (3 3) (3 3) 4

3 1 15 3 (3 3) (3 3) 5

Try It Again Use 3, 3, 7, 7 and , , to form an equation with an answer
of 25.

25Number Puzzles