Question

Callie evaluated the expression (8-2*2)3 to find 448. However, Callie’s calculations below are incorrect. Find the correct value of the expression (8-2*2)3 and explain where Callie made a mistake.

Answer 1

In step 1, when Callie distributed the One-half to the 8, she multiplied incorrectly.

Explanation:

allie solved this one-variable equation. When she was done, she tried to verify her answer, but found that it was wrong. Can you find her mistake?

1

2

(4k + 8) = 10

1. 2k + 16 = 10

2. 2k = −6

3. k = −3

What was Callie’s mistake?

Callie should have added 10 to both sides in step 2.

In step 1, when Callie distributed the One-half to the 8, she multiplied incorrectly.

Callie divided by 2 instead of multiplying by 2 in step 3.

Callie should have added 16 to both sides in step 2.

Answer 2

64

Explanation:

Callie is incorrect because of the way she distributes the exponent inside the brackets. This is what she did:

`(8 - 2*2)^3 = 8^3 - (2*2)^3 = 512 - 4^3 = 512 - 64 = 448`

The correct calculation should be done inside the bracket first, then the exponent outside

`(8 - 2*2)^3 = (8 - 4)^3 = 4^3 = 64`