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LCM, GCF, Prime Factorization Review Sheet
LCM: The Least Common Multiple is the smallest multiple that two or more numbers divide into evenly.
A multiple of a number is the product of the original number with another number.
Some multiples of 4 are 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, …
Some multiples of 7 are 7, 14, 21, 28, 35, 42, 49, 56, …
A Common Multiple is a number that is divisible by two or more numbers.
Some common multiples of 4 and 7 are 28, 56, 84, and 112.
When looking for the Least Common Multiple, you are looking for the smallest multiple that they both divide
into evenly. The least common multiple of 4 and 7 is 28.
To find least common multiples, you should break all numbers down into their prime factorization. First
consider the COMMON factors they all contain. And then use all the “LEFTOVER” factors.
By multiplying all these factors together, you will produce the LCM.
The prime factorization of 4 is 2•2
The prime factorization of 7 is 7
Since there are no common factors, use all the factors (what I call the “leftovers”),
and multiply them together to produce the LCM, which is 28.
Find the LCM for the following sets of numbers.
24 and 42 36 and 60
LCM: LCM:
