Least Common Multiple

Post on 22-May-2015

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Transcript of Least Common Multiple

Agenda Friday, Dec. 4

Homework 13 p. 239 # 1 - 13

Correct homework

Least Common Multiple

p. 234 Find GCF

9. 3, 15 = 3 10. 16, 20 = 411. 12, 36 = 1212. 11, 30 = 1

Simplify22. 10/12 = 5/623. 8/20 = 2/524. - 2/16 = -225. 25/100 = 1/426. - 120/125 = - 24/2527. 15/45 = 1/328. -20/-75 = 4/1529. 16/124 = 4/3130. - 18/81 - - 2/931. - 10/65 = - 2/1332. -14/84 = 1/6

What is the least common multiple?

The least common multiple of two numbers is the smallest number (not including 0 or 1) that is a multiple of both.

Example: What is the LCM of 3 and 4?

Multiples of 3: 3, 6, 9, 12, 15, 18... Multiples of 4: 4, 8, 12, 16, 20...

The least common multiple of 3 and 4 is 12.

Multiples of 10:

Multiples of 30:

The LCM of 10 and 30 is:

Multiples of 8:

Multiples of 24:

The LCM of 8 and 24 is:

Find the LCM of the following number pairs.

You can also find the LCM using prime factorization.

2 12 2 8 Write the prime factorization 2 6 2 4 3 2

Use the GREATEST power of 22 * 3 23 each factor.

23 * 3 8 * 3 = 24 Write the Least Common Multiple

as a product.

Use a venn diagram.

1215

3 * 52 * 2 * 3

523

2

2 * 2 * 3 * 5

22 * 3 * 5

4 * 3 * 5 = 60

Use the venn diagram just like for GCF. But multiply all the prime factors for the LCM

Find the LCM of the following expressions using the venn diagram method.

36 and 12 20 and 6

We can also use a "double ladder" method.

Find the LCM of the following number pairs using the ladder method.

8 and 15 15 and 30

Find the LCM of the following number pairs using theladder method.

32 and 12 24 and 10

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