The document provides instructions for finding the least common multiple (LCM) of two numbers. It defines key terms like multiple, common multiple, and least common multiple. It explains how to find the common multiples of two numbers by listing out their individual multiples and seeing which numbers are shared between the lists. It also introduces using prime factorizations to calculate the LCM by finding the common prime factors between the two numbers and multiplying all of the factors.
1. 5.4 Least Common Multiple
Objective: Find the least common multiple .
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Mr. Williams
GESD
jwilliams@gesd40.org
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5. Finding LCM using Prime Factors
42 60
10 6
6 7
2 5 2 3
2 3
PF = 2 x 3 x 7 PF = 2 x 2 x 3 x 5
PF = 2 x 3 x 7
PF = 2 x 2 x 3 x 5
LCM = 2 x 2 x 3 x 5 x 7
LCM = 420
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