Question

Estimate the following product by rounding off each number to nearest tens :

$1385\times 789$

Answer 1

Given, the product is $1385\times 789$.

For rounding off to the nearest tens, we first check the digit at one's place. If the digit at one's place is less than $5$ then we replace it by zero but if the digit at one's place is $\ge 5$ then we add $1$ to ten's place digit and replace one's place by zero.

We have,

$$\begin{gathered} 1385\to 1390 \\ 789\to 790 \\ 1385\times 789\to 1390\times 790 \\ =1098100 \end{gathered}$$

Hence, the required round off is $1385\times 789=1098100$.