1

Round The Number To The Nearest 10 And Add

1. 70 ------- 73 ----- 75 ------------- 80

2. 40 ----------------- 45 ------- 49 - 50 1

73 70

+ 49 +50

122 120

Answer : Actual - 122 Estimate - 120

2

Round The Number To The Nearest 100 And Add

1. 100 -------------- 150 ----154 ------- 200

2. 100 ------ 129 -- 150 ----------------- 200

1

154 200

+ 129 + 100

283 300Answer : Actual – 283 Estimate - 300

3

Round The Number To The Nearest 1000 And Add

1. 1000 ------------ 1500 ----1705 ------ 20002. 7000 ------------ 7500 --------7807--- 80003. 1000 ---1395 -- 1500 ----------------- 2000

1 1 1 1 1

31703 32000 + 47807 + 48000 + 11397 + 11000

90907 91000Answer : Actual – 90907 Estimate - 91000

4

Exercise

(a) Nearest 10

69 42 57

+ 78 + 37 + 74

. . .

(b) Nearest 100

4160 7358

+ 2397 + 5763

. .

5

Exercise

(c) Nearest 1000

26379 6942 1

+ 76689 + 43587

. .

6

ESTIMATING DIFFERENCES

7

Estimate the difference to the nearest 10 And Subtract

Solution-E.g. 8 12

1 9 2 1 9 0 - 1 6 8 - 1 7 0

0 2 4 0 2 0Ans: Actual-24 Estimate-20

8

Example 2

8 12

9 2 9 0 - 3 5 - 4 0

5 7 5 0Ans: Actual-57 Estimate-50

9

Estimate the difference to the nearest 100 And Subtract

Solution-E.g. 6 12 6 13

7 2 9 8 7 3 0 0 - 2 5 6 1 - 2 6 0 0

4 7 3 7 4 7 0 0 Ans: Actual-4737 Estimate-4700

10

Estimate the difference to the nearest 1000 And Subtract

Solution-E.g. 4 10

5 7 5 0 9 5 8 0 0 0- 4 1 3 9 9 - 4 1 0 0 0

1 6 1 1 0 1 7 0 0 0Ans:Actual-1610 Estimate-1700

11

Exercise

(a) Nearest ten9 1 8 5 6

- 6 8 - 1 3 9___ ____

(b) Nearest hundred6 1 5 8 4 6 7 2

- 4 4 2 9 - 1 0 8 5_____ _____

12

(c) Nearest thousands

4 5 6 5 0 - 2 4 7 5 6

_______