Question

Ming made a triangular picture frame out of cardboard. The sides of the frame are 6.75 in., 6.75 in., and 8.375 in. Ming uses the addition below to determine the amount of string she needs to decorate the edges of the frame.

Which explains Ming’s error?

A. She should have included the decimal in 6.75 and aligned the decimal points to add 6.750 + 6.750 + 8.375 = 21.875.
B. She forgot to put the decimal point in two of the numbers: 0.675 + 0.675 + 8.375 = 9.725..
C. She added 6.75 twice, and she should have only added it once: 6.75 + 8.375 = 15.125.
D. She should have placed a zero placeholder after the decimal point to add 6.075 + 6.075 + 8.375 = 20.525.

Answer 1

The answer is A.

Explanation:

It is A duh.

Answer 2

The answer is A. When adding decimals, you need to line up the decimal points before adding them together. To make the problems clear, adding zeroes at the end of the numbers will help make the alignment clear.

6.750
6.750
+ 8.375
21.875