MULTIPLES AND LEAST COMMON MULTIPLES Multiple The product of a whole number multiplied times any other whole number. Some multiples of 6 6, 12, 18, 24,

MULTIPLES AND

LEAST COMMON MULTIPLES

Multiple

• The product of a whole number multiplied times any other whole number.

Some multiples of 6 6, 12, 18, 24, 30, 36, 42…

Name some multiples of 5

5, 10, 15, 20, 25, 30, 35….

Name some multiples of 7

7, 14, 21, 28, 35, 42, 49….

3

Name some multiples of 4

4, 8, 12, 16, 20, 24, 28…•

Name some multiples of 9

9, 18, 27, 36, 45, 54, 63…..

Common Multiple

• A number that is a multiple of two or more numbers.

6 and 86-- 6, 12, 18, 24, 30, 36,

42,48,54,60..8– 8,16,24,

32,40,48,56,64,72,80…..

What is the Least Common Multiple of 6 & 8

• 6 = 6, 12, 18, 24, 30, 36,42,48,54,60..

• 8 = 8, 16,24,32,40,48,56,64,72,80…

What is the Least Common Multiple of 3 & 9

3 = 3, 6, 9, 12, 15, 21, 24,27,30,33…

9 = 9, 18, 27, 36, 45, 54,63,72,81,90…

The Ladder Method(SLED)

For Finding LCD, GCF,

distributive property and

Simplifying Fractions

The Ladder Method (SLED)

is a method of factoring which allows you to factor two numbers at once

in order to…• find the LCM of the two numbers• find the GCF of the two numbers• simplify a fraction with these numbers as

numerator and denominator• Finding distributive property

Use the ladder to factor6 and 8

You will divide out any common factors of the two numbers

What number goesinto both 6 and 8?

Now divide both6 and 8 by the 2

Does any # besides 1go into both 3 and 4?

No? Then you are done.ONE YOUR DONE!

Let’s find the Least Common Multiple (LCM) of

6 and 8The LCM is the product of all the

numbers on the left and the bottom.

The LCMof

6 and 8is 24.

Which numbers in the ladder give you the LCM?

The “L” shape gives you the LCM: multiply the numbers

on the left and bottom.

Let’s try some bigger numbers.

Divide out all the common factors down the left side.

What numbergoes into both

24 and 60?Does any #

besides 1go into both 12 and 30?How about6 and 15?

Anything else?No?

You’re done.ONE YOUR DONE

x

x

xx

Find the LCM.

=120

The LCMof

24 and 60is 120.

G.C.F. is to the left

L.C.M. is all of them

Becky Afghani, LBUSD Math Curriculum Office, 2003

Practice. Find the LCM and Practice. Find the LCM and

GCF for 28 and 42. GCF for 28 and 42.

LCM = 2 7 2 3 = 84

GCF = 2 7 = 14