Page 103 - Math Skill - 5

Estimation 101

Let’s Attempt

Example 1: Round off the following numbers to the nearest tens.
(a) 349 (b) 8714

Solution: (a) In 349, the digit to the right of (b) In 8714, the digit to the right
the tens place is 9. of the tens place is 4.

Since, 9 > 5 Since, 4 < 5

So, 349 is rounded off to the So, 8,714 is rounded off to the
nearest tens as 350. nearest tens as 8710.

Example 2: Round off the numbers to the nearest hundreds.
(a) 632 (b) 27,973

Solution: (a) In 632, the digit to the right of (b) In 27,973, the digit to the right
hundreds place is 3. of hundreds place is 7.
Since, 3 < 5 Since, 7 > 5

So, 632 is rounded off to the So, 27,973 is rounded off to the
nearest hundreds as 600. nearest hundreds as 28,000.

Example 3: Round off the following.
(a) 37,832 to the nearest thousands (b) 6,49,99,999 to the nearest crores

Solution: (a) In 37,832, the digit to the right of the thousands place is 8. Since, 8 > 5

So, 37,832 rounded off to the nearest thousands is 38000.

(b) In 6,49,99,999, the digit to the right of crores places is 4.
Since, 4 < 5

So, 6,49,99,999 is rounded off to the nearest crores as 60000000.

Exercise 7.1

1. Round off each of the following numbers to the nearest tens.
(a) 61 (b) 478 (c) 6,232 (d) 34,798 (e) 2,04,513

2. Round off each of the following to the nearest hundreds.
(a) 315 (b) 6,23,145 (c) 10,10,111 (d) 6,710 (e) 5,650
3. Round off each of the following to the nearest thousands.

(a) 23,670 (b) 1,84,259 (c) 5,62,789 (d) 13,50,358
4. Round off each of the following to the nearest lakhs.

(a) 2,47,689 (b) 7,16,902 (c) 10,54,319 (d) 1,63,82,547
5. Round off each of the following numbers to the nearest crores.
(a) 13,48,56,729 (b) 6,08,69,785 (c) 8,09,47,396 (d) 8,32,63,58,972