Page 33 - Whole Numbers (Addition and Subtraction)

2.3 Round off and estimate

Numbers can be rounded off to make estimates of the answers for
calculations before you do the calculations accurately.

3 567 rounded off to the nearest 10 is 3 570

3 567 rounded off to the nearest 100 is 3 600
3 567 rounded off to the nearest 1 000 is 4 000

3 565 rounded off to the nearest 10 is 3 570
3 564 rounded off to the nearest 10 is 3 560

3 550 rounded off to the nearest 100 is 3 600
3 549 rounded off to the nearest 100 is 3 500

3 500 rounded off to the nearest 1 000 is 4 000

3 499 rounded off to the nearest 1 000 is 3 000

1. Round each of these numbers off to the nearest 1 000, in the
same way as in the above examples.
(a) 6 499 (b) 6 500
(c) 4 450 (d) 4 449
(e) 3 235 (f) 3 234

(g) 7 249 (h) 7 250
(i) 7 500 (j) 7 499
(k) 6 008 (l) 6 015

2. Round each number in question 1 off to the nearest 10.
3. Round each number in question 1 off to the nearest 100.

4. Jana has already paid back R2 386 of the R4 437 she borrowed
from Petra.

(a) Round the numbers off to the nearest 1 000 and make an
estimate of how much Jana still has to pay back.

(b) Also make an estimate by rounding off to the nearest 100.

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