Grade 8 Mathematics practice questions – Lebanese curriculum

Q: Where do these Grade 8 Mathematics questions come from?

They are a sample from EduRise's Grade 8 Mathematics question bank (2,392 questions across 23 chapters), written to follow the Lebanese curriculum. Each chapter on EduRise has its own practice set and a timed exam.

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Question 1

11 divides 33 and 33 divides 66. What is the L.C.M. of 11, 33 and 66?

Accepted Answer

66. When each divides the next, the L.C.M. is the largest: 66.

Question 2

5 divides 10 and 10 divides 30. What is the G.C.F. of 5, 10 and 30?

Accepted Answer

5. When each divides the next, the G.C.F. is the smallest: 5.

Question 3

Simplify 12x/(6x) for x ≠ 0.

Accepted Answer

2. Cancel the common factor 6x: 12x/(6x) = 2.

Question 4

For which values of x is 5/(x + 2) defined?

Accepted Answer

x ≠ −2. The denominator must not be zero: x + 2 ≠ 0 → x ≠ −2.

Question 5

If x ≤ −2.7, then x − 5.5 … −8.2. Which sign?

Accepted Answer

≤. Adding −5.5 to both sides keeps the order: ≤.

Question 6

If x ≥ 4.9, then x + 3 … 7.9. Which sign?

Accepted Answer

≥. Adding 3 to both sides keeps the order: ≥.

Question 7

√100 × √49 = ?

Accepted Answer

70. √100 × √49 = 10 × 7 = 70 (also √(100 × 49)).

Question 8

√25 × √81 = ?

Accepted Answer

45. √25 × √81 = 5 × 9 = 45 (also √(25 × 81)).

Question 9

10⁴ × 10⁻⁴ = 1.

Accepted Answer

True. 10⁻ⁿ = 1/10ⁿ (positive!); scientific notation needs 1 ≤ mantissa < 10; 3 × 10⁻² = 0.03.

Question 10

10⁻³ = 0.001.

Accepted Answer

True. 10⁻ⁿ = 1/10ⁿ (positive!); scientific notation needs 1 ≤ mantissa < 10; 3 × 10⁻² = 0.03.

Question 11

A car uses 45 L of fuel for 500 km. How many litres for 900 km?

Accepted Answer

81. Direct proportionality: coefficient k = 45 ÷ 5 = 9; answer = 9 × 9 = 81.

Question 12

x and y are directly proportional. When x is multiplied by 3, y is:

Accepted Answer

multiplied by 3. Direct: y = kx, so y is multiplied by the same number.

Question 13

(a + b)² = a² + b².

Accepted Answer

False. Don't forget the double product 2ab; a² + b² does not factorise; (x + 5)² − (x − 5)² = (2x)(10) = 20x.

Question 14

(a + b)(a − b) = a² − b².

Accepted Answer

True. Don't forget the double product 2ab; a² + b² does not factorise; (x + 5)² − (x − 5)² = (2x)(10) = 20x.

Question 15

Value of (x + 4)/(x − 3) for x = −6:

Accepted Answer

2/9. (−6 + 4)/(−6 − 3) = −2/−9 = 2/9.

Grade 8 Mathematics Questions and Answers

15 Grade 8 Mathematics practice questions

1. 11 divides 33 and 33 divides 66. What is the L.C.M. of 11, 33 and 66?

2. 5 divides 10 and 10 divides 30. What is the G.C.F. of 5, 10 and 30?

3. Simplify 12x/(6x) for x ≠ 0.

4. For which values of x is 5/(x + 2) defined?

5. If x ≤ −2.7, then x − 5.5 … −8.2. Which sign?

6. If x ≥ 4.9, then x + 3 … 7.9. Which sign?

7. √100 × √49 = ?

8. √25 × √81 = ?

9. 10⁴ × 10⁻⁴ = 1.

10. 10⁻³ = 0.001.

11. A car uses 45 L of fuel for 500 km. How many litres for 900 km?

12. x and y are directly proportional. When x is multiplied by 3, y is:

13. (a + b)² = a² + b².

14. (a + b)(a − b) = a² − b².

15. Value of (x + 4)/(x − 3) for x = −6:

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