Estimating a Quotient of Whole Numbers

The whole numbers are first rounded as specified, i.e., rounded to the nearest ten, hundred and so on. Then the quotient of the rounded whole numbers is found to estimate the quotient of whole numbers.

Estimate the quotient 5873 ÷ 346 by first rounding each number so that it has only one non-zero digit.

Solution

Step 1:

Rounding 5873 such that it has only one non-zero digit means rounding it to nearest thousand. Since the hundreds digit, 8 > 5; 587󠄀3 rounds up to 6,000.

Step 2:

Rounding 346 such that it has only one non-zero digit means rounding it to nearest hundred. Since the tens digit, 4 < 5 346 rounds down to 300.

Step 3:

So the estimate of the quotient after rounding

= 6,000 ÷ 300 = 20

Estimate the quotient 2162 × 176 by first rounding each number nearest ten.

Solution

Step 1:

2162: Here the digit in ones place, 2 < 5. So 2162 rounds down to nearest ten as 2160.

Step 2:

176: Here the digit in ones place, 6 > 5. So 176 rounds up to nearest ten as 180.

Step 3:

So the estimate of the quotient after rounding

= 2160 ÷ 180 = 12