Download Section A 5-1 Least Common Multiple 5

Section A
5-1
Least Common Multiple
5-2
Adding and Subtracting with Unlike
Denominators
5-3a
Adding and Subtracting Mixed Numbers
5-3
Regrouping to Subtract Mixed Numbers
5-4
Solving Fraction Equations: Addition and
Subtraction
Section A Quiz
Section B
5-5a
5-5
5-6
5-7
Multiplying Fractions
Multiplying Mixed Numbers
Dividing Fractions and Mixed Numbers
Solving Fraction Equations: Multiplication
and Division
Section B Quiz
FRACTION OPERATIONS UNIT TEST
LESSON
5-1
Fraction Operations
Least Common Multiple
Objective
To find the least common multiple (LCM) of a group of numbers
Vocabulary
least common multiple the smallest number, other than zero, that is a multiple of
two or more given numbers
Example 1
Consumer Application
Juice comes in packs of 6, and granola bars in packs of 8. If there are 24 players, what is the
least number of packs needed so that each player has a drink and granola bar and there are
none left over?
Draw juice boxes in groups of 6. Draw granola bars in groups of 8. Stop when you have drawn the
same number of each.
There are 24 juice boxes and 24 granola bars.
Lydia’s family should buy 4 packs of juice and 3 packs of granola bars.
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Example 2
Using Multiples to Find the LCM
Find the least common multiple (LCM).
Method 1: Use a number line.
A. 3 and 4
The least common multiple (LCM) of 3 and 4 is 12.
Method 2: Use a list.
B. 3, 5, and 6
3: 3, 6, 9, 12, 15, 18, 21, 24, 30
5: 5, 10, 15, 20, 25, 30, 35
6: 6, 12, 18, 24, 30, 36, 42
The LCM of 3, 5, and 6 is 30.
Method 3: Use prime factorization.
C. 12, 10, and 15
12
2
4
×
×
2
10
3
5
×
15
2
5
×
3
Line up the common factors.
2×2×3
2
×5
3×5
2 × 2 × 3 × 5 = 60
Multiply one number from each column.
Homework:
p. 196: 1-13 odd, 14-26 even
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