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1.02 GCF and LCM

Worksheet
Greatest common factor
1

What number is a factor of every number?

2

State all the factors of each of the following numbers:

a

9

b

12

c

10

d

19

e

36

f

49

g

100

h

225

3

State whether the following numbers are a factor of 6:

a

17

b

24

c

30

d

32

e

39

f

42

g

96

h

124

4

Consider the numbers 36 and 4.

a

Find all the factors of 36.

b

Find all the factors of 4.

c

Now, find the greatest common factor of 36 and 4.

5

Consider the numbers 100 and 42.

a

Find all the factors of 100.

b

Find all the factors of 42.

c

Now, find the greatest common factor of 100 and 42.

6

Find the greatest common factor of the following groups of numbers:

a

24 and 36

b

72 and 108

c

115 and 55

d

121 and 143

e

150 and 560

f

48, 80, and 176

g

168, 312, and 120

h

168, 224, and 280

Least common multiple
7

Find the least common multiple of the following groups of numbers:

a

2 and 6

b

7 and 4

c

12 and 20

d

24 and 84

e

78 and 26

f

144 and 156

g

75, 125, and 225

h

16, 36, and 124

8

Consider the numbers 8 and 6.

a

Find the first five multiples of 8.

b

Find the first five multiples of 6.

c

Now, find the least common multiple of 8 and 6.

9

Consider the numbers 7 and 4.

a

Find the first seven multiples of 7.

b

Find the first seven multiples of 4.

c

Now, find the least common multiple of 7 and 4.

Applications
10

Three bells ring at the same time. The first rings every 63 seconds, the second every 35 seconds, and the third every 7 seconds.

After how many seconds with the 3 bells ring together again?

11

It takes Sophia 6 minutes to run 1 lap around a track, while it takes Caitlin 8 minutes to run 1 lap around the same track.

If Sophia and Caitlin start running at the same time and location on the track, after how many minutes will they next meet at the starting position?

12

It takes a particular machine 9 minutes to manufacture a flag pole, while it takes another machine 6 minutes to manufacture the same flag pole.

If both machines start at the same time, after how many minutes will the machines next begin manufacturing a flag pole at the same time again?

13

Two distance runners leave the starting line at the same time. The first distance runner takes 77 seconds to complete one lap and the second takes 99 seconds.

a

How long will it take before both distance runners meet again at the start line?

b

How many laps would the first distance runner have completed when they next meet at the start line?

c

How many laps would the second distance runner have completed when they next meet at the start line?

14

A cinema screens two different short films at two separate rooms at regular intervals throughout the day. The first film lasts for 80 minutes while the second film lasts for 50 minutes. There are 10-minute breaks between the screening of a film in each room.

If the cinema starts screening both films at 2:30 pm when it opens for the day, what is the next time that both films will start screening at the same time?

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Outcomes

MA.6.NSO.3.1

Given a mathematical or real-world context, find the greatest common factor and least common multiple of two whole numbers.

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