Question

Look at Karen's attempt to solve the equation for y: y + 8 = 15, y = 15 + 8, y = 23.Describe the mistake that Karen made.

Answer 1

The mistake that Karen made was that in order to get the 8 to switch sides, it should have been subtracted rather than added. This is because it is positive on the left side and therefore must be negative when we switch it to the right side. A proper version of this problem would be below.

y + 8 = 15

y = 15 - 8

y = 7