LCM and GCF Practice

What is the LCM of 13 and 39?

• 26
• 52
• 13
• 39

Answer explanation

Multiples of 13

13, 26, {39}, 52, 65

Multiples of 39

{39}, 78, 117, 156, 195

What is the GCF of 13 and 39?

• 13

• 39

• 1

• 3

Answer explanation

Factors of 13

1, {13}

It's a prime number.

Factors of 39

1, 3, {13}, 39

If the GCF of 45 and another number is 5, which numbers could the second number be?

(Select all correct answers)

• 5

• 9

• 10

• 15

Answer explanation

Factors of 45 are 1, 2, 3, 5, 9, 15, 45

Factors of 5 are 1,5

Factors of 9 are 1, 3, 9 (5 is not a factor of 9.)

Factors of 10 are 1, 2, 5, 10

Factors of 15 are 1, 3, 5, 15 (Since 15 is a factor of 45, the GCF of 45 and 15 is 15.)

Tags

CCSS.4.OA.B.4

Match the Statements about 14 and 35 to True or False.

7 is the GCF of 14 and 35. - (a)  

105 is the LCM of 14 and 35. - (b)  

3 is a common factor of 14 and 35 . - (c)  

70 is a common multiple of 14 and 35. - (d)  

• 7 is the GCF of 14 and 35.
• 105 is the LCM of 14 and 35.

• 3 is a common factor of 14 and 35 .

• 70 is a common multiple of 14 and 35.

• True
• False

Answer explanation

Factors of 14 are 1, 2, 7, 14

Factors of 35 are 1, 5, 7, 35

Multiples of 14 are

14, 28, 42, 56, 70, 84, 98, 112, 126, 140

Multiples of 35 are

35, 70, 105, 140, 175

Take a few minutes to start factoring 36 and 144, to use for the last two questions.

Type Mrs. Kelley's last name in the answer box for a bonus point.

(a)  

Answer explanation

Mrs. Kelley's last name is Kelley.

Her first name is not Kelly.

That is a different teacher with the same initials.

Tags

CCSS.3.OA.A.3

Ms. Yousse bought 144 pencils and 36 dry erase markers for the school year. How many groups could she make that have the same number of markers and same number of pencils in each group?

(Select ALL answers that work)

• 9

• 12

• 16

• 18

Answer explanation

Factors of 36

1,2,3,4,6,9,12,18,36

Factors of 144

1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72, 144

36 IS A FACTOR OF 144, so

ALL FACTORS OF 36 WOULD

WORK AS A NUMBER OF GROUPS

Ms. Yousse bought 144 pencils and 36 dry erase markers for the school year. How many groups could she make that have the same number of markers and same number of pencils in each group, with AT LEAST 3 markers in each group?

(Select ALL answers that work)

• 6

• 9

• 12

• 18

• 36

Answer explanation

Factors of 36

1,2,3,4,6,9,12,18,36

Factors of 144

1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72, 144

36 IS A FACTOR OF 144, so

ALL FACTORS OF 36 WOULD

WORK AS A NUMBER OF GROUPS