## 2.3.3 Standard Form, PT3 Focus Practice

Question 11: Express 0.000064−3.5× 10 −6  in standard form. Solution: 0.000064−3.5× 10 −6 =6.4× 10 −5 −3.5× 10 −6 =6.4× 10 −5 −0.35× 10 −5 =( 6.4−0.35 )× 10 −5 =6.05× 10 −5 Question 12: 200.7× 10 11  is written as 2.007× 10 b  in the standard form. State the value of b. Solution: 200.7× 10 11 =2.007× 10 2 × 10 11                   =2.007× 10 13                 b=13 Question … Read more

## 2.3.2 Standard Form, PT3 Focus Practice

Question 6: (a)  Round off 0.05079 correct to three significant figures. (b)  Find the value of 5 × 107 + 7.2 × 105 and state its answer in standard form. Solution: (a)  0.05079 = 0.0508 (correct to three significant figures) (b)  5 × 107 + 7.2 × 105 = 500 × 105 + 7.2 × … Read more

## 2.3.1 Standard Form, PT3 Focus Practice

Question 1: Round off each of the following numbers to the number of significant figures indicated in brackets. (a) 80616 (3 s. f.) (b) 60932 (3 s. f.) (c) 0.4783 (2 s. f.) (d) 3.047 (3 s. f.) (e) 0.00567 (2 s. f.) (f) 0.05086 (3 s. f.) Solution: (a) 80600 (b) 60900 (c) 0.48 … Read more

## 2.2.2 Standard Form (Part 2)

Example 1: Find the value of 7.3 × 103 + 3.2 × 104 and express your answer in standard form. Solution: 7.3 × 103 + 3.2 × 104 = 7.3 × 103 + 3.2 × 101 × 103 = [7.3 + (3.2 × 101)] × 103 = 39.3 × 103 = 3.93 × 104 Example 2: … Read more

## 2.2.1 Standard Form (Part 1)

2.2.1 Standard Form (Part 1) 1. Standard form is a way of writing very large numbers or very small numbers in the form of A × 10n, where  1 ≤ A < 10  and n is a positive or a negative integer. Example 1: Express each of the following numbers in standard form. (a) 7244 (b) 32567 … Read more

## 2.1.2 Significant Figures (Part 2)

2.1.2 Significant Figures (Part 2) 1. Perform combined operations (addition, subtraction, multiplication and division) involving numbers, the final answer is rounded off to specific significant figures.  Example: Find the value of each of the following and give your answer correct to 3 significant figures. (a) 261.9 + 75.6 × 0.7 (b) 0.062 × 30.12 + 1.268 (c)  8.608 ÷ 0.08 … Read more

## 2.1.1 Significant Figures (Part 1)

2.1.1 Significant Figures (Part 1) 1. Significant figures are the relevant digits in an integer or a decimal number which has been rounded up to a value according to a degree of accuracy. 2. In rounding off positive numbers to a given number of significant figures, the significance of zero is shown as below. (a) … Read more