Page 61 - Mathematics

Exercise 3.4

In question 1 to 10, estimate the value of each of the given expressions.

1. 43 28× 4. 868 31× 7. 35 164 23.04×
2. 2 912 32× 5. 2.94 248× 8. 1.029 0.021÷
3. 82 61× 6. 171 220 79÷ 9. 4 981 6 438÷ Tanzania Institute of Education
10. 9 110 218 800 4 081÷
11. A shopkeeper sold 192 t-shirts at a price of 5,950 Tanzanian shillings
each. By estimation, how much money did the shopkeeper get?
12. A village received 40,376 bags of fertilizer to be distributed to 392
farmers. Estimate the number of bags each farmer got.
13. Estimate the answers of each of the following expressions.
(a) 25.45 268÷ (c) 528 3 902× (e) 824 325−
(b) 1.0031 56.241+ (d) 61 24÷
14. Find the approximate answers to each of the following:
21.3 1
(a) (c) 67.3×
0.11 4.96
42.3 2.81×
(b) 4.93 2.14× (d)
20.5

15. Amina and her 17 friends bought 212 bottles of soft drink at a price of
Tshs 635 per bottle. If the total cost was shared equally among themselves,
estimate how much each person paid.
16. Estimate the number of 46 cm by 46 cm tiles which will be required to
cover a room measuring:
(a) 3.84 m by 2.98 m
(b) 6.41 m by 3.28 m
(c) 4.29 m by 4.6 m

Chapter summary

1. Approximating or rounding off a number is a process of writing a number
close enough to the exact number.
2. During approximation, if the digit to the right is 5, the rounding digit is:
(i) increased by 1 if it is odd. Mathematics Form One
(ii) left unchanged if it is even and has zero digits after 5 or has no digit
after 5.

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Mathematics form 1.indd 55