Question

I need help also I did not mean to click c so that might not be the answer so please don't put c as your answer unless you are certain that c is the answer.

Answer 1

D. (43 +60) +40

Explanation:

The purpose of changing the grouping in addition problems is to simplify the mental effort required as much as possible. This will generally mean grouping ...

• "complementary" numbers,
• numbers with the same number of leading or trailing zeros,
• numbers with the same sign, and
• fractions with the same denominator.

Analysis

A. Numbers ending in 0 are already grouped; no change is needed.

B. Fractions with the same denominator are already grouped; no change is needed.

C. Numbers with the same (negative) sign are already grouped; no change is needed.

D. Numbers ending in zero could be grouped to make addition easier:

43 +(60 +40) . . . . regrouping would be useful

We also note that in A and D, the sum of numbers ending in zero is 100, so these numbers are "complements" of each other. This is another reason for grouping them together.