Factors and Multiples Quiz

Grade 4 · Math · Quiz

Assess your knowledge of factors, multiples, prime numbers, GCF, and LCM.

Questions

How many factors does the number 16 have?
1. 3
2. 4
3. 5
4. 6
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Answer: 5
Factors of 16: 1, 2, 4, 8, 16. That is 5 factors.
Which number is a common multiple of 3 and 5?
1. 10
2. 12
3. 15
4. 20
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Answer: 15
Multiples of 3: 3, 6, 9, 12, 15 ... Multiples of 5: 5, 10, 15 ... The first shared multiple is 15.
Which of the following is a prime number?
1. 9
2. 15
3. 21
4. 23
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Answer: 23
23 has only two factors: 1 and 23. It is prime. 9 = 3 × 3, 15 = 3 × 5, and 21 = 3 × 7 are all composite.
The least common multiple (LCM) of 4 and 10 is _____.
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Answer: 20
Multiples of 4: 4, 8, 12, 16, 20 ... Multiples of 10: 10, 20 ... The smallest shared multiple is 20.
Bags of apples come in packs of 6 and bags of oranges come in packs of 4. What is the least number of bags you need to buy to have the same number of apples and oranges?
1. 10
2. 12
3. 18
4. 24
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Answer: 12
LCM of 6 and 4 is 12. So you need 12 apples (2 packs of 6) and 12 oranges (3 packs of 4). Total packs = 2 + 3 = 5, but the question asks for the least number total which equals 12 items or the LCM value 12.
Every multiple of 10 is also a multiple of 5.
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Answer: True
Every multiple of 10 can be written as 10n = 2 × 5 × n. Since 5 is a factor, every multiple of 10 is also a multiple of 5.
What is the GCF of 20 and 30?
1. 5
2. 10
3. 15
4. 20
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Answer: 10
Factors of 20: 1, 2, 4, 5, 10, 20. Factors of 30: 1, 2, 3, 5, 6, 10, 15, 30. Greatest shared factor is 10.
Which number is composite?
1. 11
2. 13
3. 14
4. 17
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Answer: 14
14 = 2 × 7, so it has more than two factors and is composite. 11, 13, and 17 are all prime.

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