Question

Two of your friends, Matt and Karen, both run to you to settle a dispute. They were working on a math problem, and got different answers. Wisely, you decide to look at their work to see if you can spot the source of confusion.

Matt
6 – 4(3 – 5)2 + 30 ÷ 5
6 – 4(–2)2 + 30 ÷ 5
6 – 4(4) + 30 ÷ 5
6 – 16 + 30 ÷ 5
−10 + 30 ÷ 5
20 ÷ 5
4
Karen
6 – 4(3 – 5)2 + 30 ÷ 5
6 – 4(–2)2 + 30 ÷ 5
6 – 4(−4) + 30 ÷ 5
6 + 16 + 30 ÷ 5
6 + 16 + 6
22 + 6
28

Answer 1

Karen is correct, because in step two, matt multiplied 2 and -2, and got 4. instead, 2*-2 should be what Karen got; -4.