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

Answer 1

Andrew's mental math strategy breaks down the addition of the hours worked on his project into manageable steps. Let’s verify his calculation:

1. First, he grouped the hours worked in the first and third weeks:

   • 6.6 hours (first week) + 4.4 hours (third week) = 11.0 hours

2. Then, he added the hours worked in the second week:

   • 11.0 hours + 2.75 hours (second week) = 13.75 hours

So, Andrew's total working hours for the project is 13.75 hours, and his strategy and calculations are correct!