Page 14 - SM Class 4 Inner.cdr

Rounding off Numbers

To nearest 10
To round off a number to nearest 10, we observe the last digit (ones). If ones

digit is 0, 1, 2, 3 or 4, we replace it with zero (0), But if ones digit is 5, 6, 7, 8 or

9, we replace it with zero (0) and increase the tens digit by 1.
For example;
143 is round off to 140 (3 is ones digit)

1857 is round off 1860 (7 is ones digit)

45628 is round of to 45630 (8 is ones digit)
To nearest 100

To round off a number to nearest 100, we look at the tens digit. If tens digit is 0,

1, 2, 3 or 4, we replace it and ones digit by 0. If tens digit is 5, 6, 7, 8 or 9, we
replace it and ones digit by 0 and increase hundred digit by 1.

893 is round off to 900
14372 is round off to 14400

45341 is round off to 45300
To nearest 1000

To round off a number to nearest 1000, we look at the hundred digit. If

hundreds digit is 0, 1, 2, 3 or 4, we replace it, tens digit and ones digit with 0. If
hundreds digit is 5, 6, 7, 8 or 9, we replace it, tens digit and ones digit with 0

and increase the thousand digit by 1.
17389 is round off to 17000

643821 is round off to 644000
326548 is round off to 327000

E xercise 1.3

1. Round off to nearest 10.
a. 593 b. 7865 c. 24582
d. 172872 e. 148936 f. 12458
g. 683279 h. 273621

2. Round off to nearest 100
a. 178924 b. 67258 c. 13285
d. 24049 e. 401402 f. 396907

g. 563469 h. 699452

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Mathematics In Focus - 4