This document outlines steps for finding the least common multiple (LCM) of numbers and fractions. It provides examples of finding the LCM of various numbers and algebraic expressions. It also explains how to compare fractions by first finding a common denominator and then comparing the numerators. The document concludes by providing homework problems involving finding LCMs and comparing fractions.

1. 5.1 LCM & Comparing Fractions November 17, 2011
Bellwork
Write the prime factorization of each number.
(factor tree)
1. 20 2. 621
3. Place the following numbers in order from
least to greatest: 4, 1/2, ­3, ­2/3, 1/4
Objective ­ find the least common multiple & compare fractions
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2. 5.1 LCM & Comparing Fractions November 17, 2011
A multiple of a number is the product of that number and any nonzero number.
Multiples of 4:
Multiples of 6:
Today, both the baseball and soccer teams had games.
The baseball team plays every 6 days. The soccer team plays every 5 days.
When will both teams have games on the same day again?
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3. 5.1 LCM & Comparing Fractions November 17, 2011
Find the LCM of 12 and 40
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4. 5.1 LCM & Comparing Fractions November 17, 2011
Find the LCM.
6, 16 9, 15 12, 15, 18
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5. 5.1 LCM & Comparing Fractions November 17, 2011
Find the LCM
6a2, 18a3
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6. 5.1 LCM & Comparing Fractions November 17, 2011
Find the LCM
2 4 2
12x, 15xy 8m , 14m 25y , 15x
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7. 5.1 LCM & Comparing Fractions November 17, 2011
When fractions have different denominators, rewrite the fractions
with a common denominator. Then compare the numerators.
The math team won 5/8 of its competitions and the debate team won 7/10
of its competitions. Which team won the greater fraction of competitions?
Steps:
1. Find the LCM of 8 and 10
2. Write equivalent fractions with the new denominator.
3. Compare the fractions
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8. 5.1 LCM & Comparing Fractions November 17, 2011
Compare the fractions in each pair.
6 , 4 ­3 , ­7
7 5 4 10
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9. 5.1 LCM & Comparing Fractions November 17, 2011
Order 1/2, 3/4, and 2/5 from least to greatest. Change to LCD first.
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10. 5.1 LCM & Comparing Fractions November 17, 2011
HW pg. 235 # 1 ­ 37 odds
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