Question

Which is the best estimate of the following sum? 5 3/8 + 7 7/8 = ?a.11b.12c.13d.14

Answer 1

`\begin{gathered} 5(3)/(8)=(40+3)/(8)=(43)/(8) \\ 7(7)/(8)_{}=(56+7)/(8)=(63)/(8) \\ \to(43)/(8)+(63)/(8)=(43+63)/(8)=(106)/(8)=13.25\approx13 \end{gathered}`