Page 51 - Mathematics

7. Find the value of each of the following, and round off the answers to the
nearest tenths.
(a) 2,684 ÷ 17 (c) 0.33 ÷ 1.1
(b) 4,314 ÷ 430 (d) 5,301 ÷ 18
8. Convert each of the following fractions into decimals and round off the
answers to the nearest tenths. 1 Tanzania Institute of Education
2
(a) (b) 3 (c) 17 (d)
9 7 3 4

9. Consider the following numbers: 9, 2.1, 42.045, and 635.7891.
(a) Add all the given numbers.
(b) Round off the number obtained in (a) to the nearest:

(i) Hundredths (ii) Tenths (iii) Hundreds

10. A factory got a profit of Tshs 67,459,853 after selling its products. How
much profit did the factory get to the nearest thousands?
11. An electrician used 12,789 m, 13,952 m, and 9,374 m lengths of wire

in 3 different months, respectively.
(a) Find the average amount of wire used to the nearest hundreds for
the three months
(b) What is the difference between the actual amount and the estimated
amount?

Rounding off by number of decimal places
Rounding off decimals involves a similar process of rounding numbers by place
values. When rounding off decimals, the digits to the right of the given decimal
place are dropped rather than being replaced by zeros.
In the process of rounding off, the following steps are used:
(a) If the digit after the rounding digit is either 0, 1, 2, 3, or 4, then the rounding
digit remain unchanged, and all the other digits to the right are dropped.

Example 3.8

Round off 0.2464 to 3 decimal places.

Solution Mathematics Form One
The digit in the third decimal place is 6 and the nearest digit to the right is 4
which is less than 5. In this case, 6 will remain unchanged and 4 is dropped.
Therefore, 0.2464 ≈ 0.246 to 3 decimal places.

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