Question

Andrew used the following mental math strategy to find the total number of hours he worked on his project.6.6+2.75+4.46.6+2.75+4.4(6.6+4.4)+2.756.6+4.4+2.75 11+2.75=13.7511+2.75=13.75  What is the reason for his strategy?

Answer 1

$\begin{gathered} 6.6+2.75+4.4 \\ (6.6+4.4)+2.75 \\ \text{ He grouped 6.6 and 4.4 because the result is an integer:} \\ 6.6+4.4=11 \\ \text{Therefore it will be easier to add} \\ 11+2.75=13.75 \end{gathered}$