Page 55 - Mathematics

10. Using a calculator or otherwise, evaluate the following and give the
answer in specified number of decimal places.
27 3.648×
(a) (2 decimal places)
4.8954
(b) 10.64 13.28× (3 decimal places)
14.32 4.893× Tanzania Institute of Education

(c) 2.84 1.2+ (1 decimal place)
6.28 3.49−

(d) 153.4 6.5÷ (1 decimal place)
(e) 44.0561 11÷ (2 decimal places)
(f) 0.001144 0.056÷ (3 decimal places)
11. If the length of a square plate is 3.14m, calculate its area correct to 3
decimal places.
12. Evaluate each of the following expressions and write your answer
according to the given instructions.

(a) 531.7 4.3÷ (1 decimal place)
(b) 21.0561 14÷ (1 decimal place)
(c) 0.001432 0.076÷ (3 decimal places)

Significant figures
A significant figure is a digit in a number that gives information about the precision
and accuracy of the measured value.

Rules for significant figures
1. Any digit from 1 to 9 appearing in a number is a significant figure.
2. Each zero appearing in a number between digits 1 to 9 is a significant figure. For
example, 0 in 602 is a significant figure. That is, 602 has 3 significant figures.
3. When zeros are written to the right of the last non-zero digit, the zeros are not
significant figures. For example, 72,000 has only 2 significant figures.
4. In decimals, any zero to the left of the first non-zero digit is not a significant
figure. For example, the zeros in 0.025 are not significant figures. Thus, 0.025

has 2 significant figures.
5. All zeros that are on the right of a decimal point are significant only if a non- Mathematics Form One
zero digit does not follow them. For example, 0.040 has two significant figures
while 0.6700 has four significant figures, and 10.000 has five significant figures.

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25/10/2024 09:51:14
Mathematics form 1.indd 49
Mathematics form 1.indd 49 25/10/2024 09:51:14