Lesson 30

​Least common multiple

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​Reciprocals

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​Multiples are numbers multiplied to show factors

2: 2, 4, 6, 8, 10, 12

3: 3, 6, 9, 12. 15​

​Reciprocals are numbers who multiplied

together ​equal 1

Flip the numerator and denominator​

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Reciprocal of 1/2

​reciprocal of 5

Least common multiples

• Will be used when finding common denominators

​How to:

1. list the multiples of each number

2. find the lowest multiple that each have in common

​What it the least common multiple of 3 and 4?

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3:

4:​

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What is the LCM of 2 and 4

2:

4:​

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Find the least common multiple​

​6 and 8 3 and 5 5 and 10

Reciprocals:

2 numbers whose product is 1

Flip the fraction​

​All numbers can have a fraction (whole numbers too!

Terms:​

​reciprocal of 1/2 is 2/1

reciprocal of 5 is 1/5​

​Reciprocals

How many 2/3 are in 1?

• This means ​2/3 x ___ = 1

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5/6 x ___ = 1

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Reciprocals​

​Write the reciprocal of each

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6

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2/3

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8/5

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1/3​

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​3/8 x ___ = 1

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4 x ___ = 1

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___ x 7/8 = 1

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___ x 1/6 = 1 ​

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​How many 2/5 are in 1​?

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How many 5/12s are in 1?​

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