Andrew was making a science project for school. He worked for 6.6 hours the first week, 2.75 hours the second week, and 4.4 hours the third week.

Question

Andrew used the following mental math strategy to find the total number of hours he worked on his project.

6.6+2.75+4.4

(6.6+4.4)+2.75
 

11+2.75=13.75

 

 

What is the reason for his strategy?

(1 point)
Responses

It is easier to add decimals in a decreasing order than in a mixed order.

It is easier to add decimals in a decreasing order than in a mixed order.

6.6 and 4.4 are compatible numbers that are easy to add mentally.

6.6 and 4.4 are compatible numbers that are easy to add mentally.

It is easier to add decimals with the same number of place values after the decimal point than adding decimals with different numbers of place values after the decimal point.

It is easier to add decimals with the same number of place values after the decimal point than adding decimals with different numbers of place values after the decimal point.

Rounding removes the decimals and creates whole number

Answer 1

The reason for Andrew's strategy is:

6.6 and 4.4 are compatible numbers that are easy to add mentally.

By grouping 6.6 and 4.4 together, he can quickly calculate their sum as 11, which simplifies the mental math process before adding the remaining 2.75.