Prime Factorization Worksheets

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41.

List all the prime numbers greater than 20 and less than 30.

a. | 23, 31, 29 | ||

b. | 23 and 27 | ||

c. | 23 and 29 | ||

d. | 17 and 19 |

List of prime numbers greater than 20 and less than 30 are 23 and 29.

Correct answer : (3)

42.

Identify a number that is a multiple of 15.

a. | 384 | ||

b. | 225 | ||

c. | 275 | ||

d. | 366 |

The numbers 384, 366, and 275 do not leave remainder zero when divided by 15.

The number 225 leaves a remainder zero when divided by 15.

Therefore, 225 is a multiple of 15.

Correct answer : (2)

43.

Which of the following is a factor of 121?

a. | 14 | ||

b. | 12 | ||

c. | 11 | ||

d. | 13 |

So, 11 is one of the factors of 121.

Correct answer : (3)

44.

Which of the following is a multiple of 25?

a. | 625 | ||

b. | 112 | ||

c. | 135 | ||

d. | 220 |

The numbers 112, 135, and 220 do not leave remainder zero, when divided by 25.

The number 625 leaves a remainder zero, when divided by 25.

So, 625 is a multiple of 25.

Correct answer : (1)

45.

Identify the prime number.

a. | 57 | ||

b. | 9 | ||

c. | 13 | ||

d. | 33 |

Factors of 9 : 1, 3 and 9

Factors of 33 : 1, 3, 11, and 33

Factors of 57 : 1, 3, 19, and 57

Factors of 13 : 1 and 13

The numbers 9, 33, and 57 have more than 2 factors.

So, the number 13 is a prime number.

Correct answer : (3)

46.

Identify a prime number.

a. | 107 | ||

b. | 51 | ||

c. | 121 | ||

d. | 93 |

Factors of 51 : 1, 3, 17, and 51

Factors of 121 : 1, 11, and 121

Factors of 93 : 1, 3, 31, and 93

Factors of 107 : 1 and 107

The numbers 51, 121, and 93 have more than 2 factors.

So, the number 107 is a prime number.

Correct answer : (1)

47.

Identify a composite number.

a. | 113 | ||

b. | 59 | ||

c. | 35 | ||

d. | 71 |

Factors of 59 : 1, and 59

Factors of 71 : 1 and 71

Factors of 113 : 1 and 113

Factors of 35 : 1, 5, 7, and 35

The number 35 has more than two factors.

So, the number 35 is a composite number.

Correct answer : (3)

48.

Identify a prime number.

a. | 121 | ||

b. | 109 | ||

c. | 93 | ||

d. | 39 |

Factors of 39: 1, 3, 13, and 39.

Factors of 121 : 1, 11, and 121.

Factors of 93 : 1, 3, 31, and 93.

Factors of 109: 1 and 109.

The numbers 39, 121, and 93 have more than 2 factors.

So, the number 109 is a prime number.

Correct answer : (2)

49.

Identify a composite number.

a. | 119 | ||

b. | 31 | ||

c. | 71 | ||

d. | 51 |

Factors of 31: 1 and 31

Factors of 71: 1 and 71

Factors of 119: 1 and 119

Factors of 51: 1, 3, 17, and 51

The number 51 has more than two factors.

So, the number 51 is a composite number.

Correct answer : (4)

50.

Find all the common factors of 16, 28, and 32.

a. | 1, 2, 4, 5, and 10 | ||

b. | 1, 2, and 4 | ||

c. | 32, 56 and 64 | ||

d. | 1, 2, 3 and 4 |

[Write the pairs of numbers with a product of 16.]

The factors of 16 are 1, 2, 4, 8 and 16.

28 = 1 × 28, 2 × 14, 4 × 7

[Write the pairs of numbers with a product of 28.]

The factors of 28 are 1, 2, 4, 7, 14 and 28.

32 = 1 × 32, 2 × 16, 4 × 8

[Write the pairs of numbers with a product of 32.]

The factors of 32 are 1, 2, 4, 8, 16 and 32.

The common factors of 16, 28 and 32 are 1, 2 and 4.

Correct answer : (2)