Lesson 12, Topic 4
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# Numbers less than Zero

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The number 0.000 765 is given 6 decimal places. The zero before the decimal number means that there are no units and the three zeros after the decimal point mean that there are no tenths, no hundredths, and no thousandths, so the four zeros are not significant or the first significant figure.

Therefore, the most significant or first significant figure is 7. The second significant figure is 6 and the third significant figure is 5.

Note: the first significant figure is always the first non-zero figure as you read a number from the left.

### Example:

Round off 246. 006 correct to:

i. 1 s.f
ii. 2 s.f
iii. 3 s.f
iv. 4 s.f
v. 5 s.f

Solution

i. 246 . 006 = 200 correct to 1  s.f.

ii. 246 . 006 = 250 correct to  2  s.f.

iii. 246 . 006 = 246 correct to 3  s.f.

iv. 246 . 006 = 246.0 correct to 4  s.f.

(Note that the zero after the decimal point in the answer is necessary to show four significant figures.

v. 246 . 006 = 246.01 correct to 5  s.f.

#### Responses error: