10 questions · Form 3 Mathematics Bab 2: Standard Form
Calculate 6.2 × 10⁵ - 4.1 × 10⁴.
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. Calculate 6.2 × 10⁵ - 4.1 × 10⁴.
Answer: D
6.2 × 10⁵ - 0.41 × 10⁵ = (6.2 - 0.41) × 10⁵ = 5.79 × 10⁵.
2. Round 0.08472 to 2 significant figures.
Answer: A
Target position is 4. The following digit is 7 (≥ 5), so round up 4 to 5. Result: 0.085.
3. Calculate (8 × 10⁻³) ÷ (4 × 10⁻⁷).
Answer: B
(8 ÷ 4) × 10⁻³⁻⁽⁻⁷⁾ = 2 × 10⁻³⁺⁷ = 2 × 10⁴.
4. Calculate (5.4 × 10⁻³) - (2.1 × 10⁻⁴) in standard form.
Answer: C
5.4 × 10⁻³ - 0.21 × 10⁻³ = (5.4 - 0.21) × 10⁻³ = 5.19 × 10⁻³.
5. How many significant figures does the number 300.00 have?
Answer: C
Trailing zeros after a decimal point are significant. All 5 digits (3, 0, 0, ., 0, 0) are significant.
6. Calculate (2 × 10⁴) × (3 × 10⁻⁶).
Answer: A
(2 × 3) × 10⁴⁺⁽⁻⁶⁾ = 6 × 10⁻².
7. Express 3.6 × 10⁻³ as a single number in normal decimal form.
Answer: C
3.6 × 10⁻³ means moving the decimal point 3 places to the left: 0.0036.
8. Calculate (3.6 × 10⁻⁴) ÷ (9 × 10⁻²).
Answer: A
(3.6 ÷ 9) × 10⁻⁴⁻⁽⁻²⁾ = 0.4 × 10⁻² = 4.0 × 10⁻³.
9. Round 49,960 to 3 significant figures.
Answer: A
Target position is the second 9. Next digit is 6 (≥ 5), rounding up gives 50,000 (which represents 3 s.f. in this context).
10. Which of the following numbers is written in Standard Form?
Answer: C
Standard Form is written as A × 10ⁿ where 1 ≤ A < 10 and n is an integer. 4.5 satisfies 1 ≤ 4.5 < 10.