Multiples, Factors, and Prime Numbers Worksheet

Question 1

List the first 5 multiples of 4.

Accepted Answer

The first 5 multiples of 4 are 4, 8, 12, 16, and 20.

Question 2

List all the factors of 12.

Accepted Answer

The factors of 12 are 1, 2, 3, 4, 6, and 12 because each of these numbers divides 12 evenly.

Question 3

Tell whether 17 is prime or composite. Explain how you know.

Accepted Answer

The number 17 is prime because it has exactly 2 factors, 1 and 17.

Question 4

Write the first 6 multiples of 7.

Accepted Answer

The first 6 multiples of 7 are 7, 14, 21, 28, 35, and 42.

Question 5

Find all the factor pairs of 18.

Accepted Answer

The factor pairs of 18 are 1 and 18, 2 and 9, and 3 and 6.

Question 6

Circle all the prime numbers: 9, 11, 13, 15, 19.

Accepted Answer

The prime numbers are 11, 13, and 19 because each has exactly 2 factors.

Question 7

Find the greatest common factor of 8 and 12.

Accepted Answer

The greatest common factor of 8 and 12 is 4 because 4 is the largest number that divides both 8 and 12 evenly.

Question 8

Find the least common multiple of 3 and 5.

Accepted Answer

The least common multiple of 3 and 5 is 15 because 15 is the smallest number that is a multiple of both 3 and 5.

Question 9

Is 21 a multiple of 3, a factor of 42, or both? Explain.

Accepted Answer

The number 21 is both because 21 equals 3 times 7, so it is a multiple of 3, and 42 divided by 21 equals 2, so it is a factor of 42.

Question 10

List all the factors of 20.

Accepted Answer

The factors of 20 are 1, 2, 4, 5, 10, and 20.

Question 11

Write the first 4 common multiples of 2 and 3.

Accepted Answer

The first 4 common multiples of 2 and 3 are 6, 12, 18, and 24.

Question 12

Tell whether 1 is prime, composite, or neither. Explain your thinking.

Accepted Answer

The number 1 is neither prime nor composite because it has only 1 factor.

Question 13

Find the missing number: 5, 10, 15, __, 25. Tell what pattern you used.

Accepted Answer

The missing number is 20. The pattern is counting by 5s, so each number is a multiple of 5.

Question 14

Find the greatest common factor of 15 and 25.

Accepted Answer

The greatest common factor of 15 and 25 is 5 because 5 is the largest factor they both share.

Question 15

A number has exactly 2 factors, 1 and itself. What kind of number is it? Give one example.

Accepted Answer

This kind of number is called a prime number. One example is 7 because its only factors are 1 and 7.

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