Question

Round each addend to the nearest ten

Estimate the sum

Answer 1

Rounding off the given numbers to nearest ten,

$$\begin{gathered} 31\underset{Roundedofftonearestten}{\to }30 \\ 81\underset{Roundedofftonearestten}{\to }80 \end{gathered}$$

Now, estimated sum is

$$\begin{gathered} =30+80 \\ =110 \end{gathered}$$

Hence, the estimated sum will be $110$