Page 70 - Math Course 1 (Book 1)

LCM (Least Common Multiple)

Mo. 2

Lesson 3
Let’s Begin

KEY CONCEPTS: Find the LCM
1. Find the least common multiple of two or
more numbers.
2. Find the least common multiple of two or Example
more fractions.

Find the LCM of 168 and 180.
MO. 2 - L3a
Prime Exponential
Number
Finding the LCM Factorization Form
of Numbers 168 2 2 2 3 7 2³ 3 7

Vocabulary A-Z 180 2 2 3 3 5 2² 3 5
2
Let us learn some vocabulary
The prime factor of both numbers are 2, 3, 5, and
7. Multiply the greatest power of 2, 3, 5, and 7
appearing in either factorization.

Multiple LCM = 2³ 3² 5 7
is a product of that number and a whole number.
= 2520
multiples of 4 : 4, 8, 12, 16, 20, 24, 28,...
Answer The LCM of 168 and 180 is 2520

Common Multiples
Sometimes numbers have some of the same
multiples. These are called common multiples. The LCM of Monomials

multiples of 4 : 4, 8, 12, 16, 20, 24, 28,... Example

multiples of 6 : 6, 12, 18, 24, 30, 36, 42,...
Find the LCM of 12x²y² and 6y³.

Some common multiples of 4 and 6 are 12, 12x²y² = 2² 3 x² y² Find the prime factoriza-
and 24 tion of each monomial.
6y³ = 2 3 y³ Highlight the greatest
power of each prime factor
Least Common Multiple (LCM)
LCM = 2² 3 x² y³ Multiply the greatest
The least of the nonzero common multiples is called power of each prime factor.
the least common multiple (LCM).
= 12x²y³
multiples of 4 : 4, 8, 12, 16, 20, 24, 28,...

The LCM of 12x²y² and 6y³
multiples of 6 : 6, 12, 18, 24, 30, 36, 42,... Answer
is 12x²y³

LCM of 4 and 6 is 12

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