Open Middle®
Directions: Using the digits 0 to 9, at most one time each, place a digit in each box to make the equation true.
Hint
How can we pair up the numbers so that all the pairs are equivalent?
Answer
Each pair should add up to 9, for example 4 + 5 = 1 + 8…and so on
Source: Graham Fletcher
This is an example of running equal signs. There can only be one equal sign in an equation.
Running equal signs is an issue when one completes one equation and then creates a new equation next to it, eg. 3+5 = 8 + 2 = 10, but when all of the expressions are equivalent, it is mathematically correct.
Thanks
Thanks