Least Common Multiple (LCM)

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Show your work for each problem.

1.
What is the LCM of and ?
1. a)6
2. b)5
3. c)3
4. d)1
2.
Find the LCM of and .
3.
Find the LCM of and by listing multiples.
4.
Which statement about LCM is TRUE?
1. a)LCM is always smaller than both numbers
2. b)LCM is the same as GCF
3. c)LCM is always the product of two numbers
4. d)LCM is the smallest common multiple
5.
Find the LCM of and .
6.
Use prime factorization to find the LCM of and .
7.
If , what must be true?
1. a)a divides b evenly
2. b)a and b are coprime
3. c)b divides a evenly
4. d)a equals b
8.
Bus A arrives every minutes and Bus B arrives every minutes. If both arrive now, when will they arrive together again?
9.
Find the LCM of and .
10.
Find the LCM of , , and .
11.
Find the LCM of and .
12.
What is the LCM of , , and ?
1. a)180
2. b)240
3. c)120
4. d)60
13.
To add , what is the LCD (least common denominator)?
14.
If and , what is ?
15.
Two lights flash. One flashes every seconds, the other every seconds. If they flash together now, when will they flash together again?
1. a)54 seconds
2. b)36 seconds
3. c)15 seconds
4. d)18 seconds