Question

3 - 4 - 7
=3 - (4 - 7) step 1
=3 - (-3) step 2
=6 step 3
find keishas first mistake.
choose 1 answer:
a changing the groups changes the differences value.
b 4 minus 7 equals 3, not -3
c 3 minus -3 equals 0, not 6.

Explanation:

Step1: Analyze the operation order

The original expression is $3 - 4-7$. In arithmetic, subtraction is not associative. We cannot group the terms as $3-(4 - 7)$ without changing the value. The correct way to calculate is from left - to - right.

Step2: Check the error in the step

The error occurs in Step 1 when the grouping is changed. Changing the groups in a subtraction operation changes the difference's value.

Answer:

A. Changing the groups changes the difference's value.