Quote of the Day:Quote of the Day:

Fact: Thomas Edison invented over 1000 inventions besides the light bulb

Facts about Thomas Edison

Fact: Thomas Edison did look at it at 1000 failures before the light bulb was invented instead…..he looked at it as 1000 ways the light bulb did not work. Could you continue with a that kind of positive attitude?

Math is not about perfection…its about continuing on until accuracy is obtained.

LCM(least common multiple)

Created by Ms. Layne

Review Common Multiple

A common multiple is a number that is a multiple of two or more numbers. What are the common multiples of 3 and 4?

Hint: Remember a multiple must start Remember a multiple must start with the number and expand or grow with the number and expand or grow biggerbigger

(a multiple can never ever be smaller than the original number)

Multiples of 3 – 3, 6, 9, 12, 15, 18, 21, 24 Multiples of 4 – 4, 8, 12, 16, 20, 24 Therefore the common multiples of 3 and 4

are…. 12 and 24

LCMLeast Common Multiple

Definition The least common multiple (LCM) of two

numbers is the smallest number that is a multiple of both.

Let’s look at our example of common multiples of 3 and 4….

12 and 24 – What is the leastleast common multiple?

The LCM of 3 and 4 is 12.

3 Methods of LCM3 Methods of LCM

1. Multiples – Old School Way 2. Factor Tree – using a factor tree

to determine the LCM 3. The upside down birthday cake –

the upside down cake returns to show us an easy way to determine the LCM

Method 1 - MultiplesMethod 1 - Multiples 1. Write out the long way multiples of each

number. Remember to start each number with itself

than continue on (look at a multiplication table it is multiples of that number.

For video help please go to study jams: http://studyjams.scholastic.com/

studyjams/jams/math/fractions/least-common-multiple.htm

Example will be done in class using 6 and 8.

Method 1 - MultiplesMethod 1 - Multiples More Examples

Method 2 – Factor TreeMethod 2 – Factor Tree 2. Factor Trees

1. make a factor tree using 6 and 8. 2. Write out horizontal the prime factors in each

number. 3. Circle the numbers they have in common and

only use them once. 4. Rewrite all prime factors of both numbers only

using the common numbers once. 5. Multiply them all together to get the LCM. For video help see study jams:

http://studyjams.scholastic.com/studyjams/jams/math/fractions/least-common-multiple.htm

Example in class will be done using same Example in class will be done using same numbers 6 and 8.numbers 6 and 8.

More Examples

Method 2 – Factor TreeMethod 2 – Factor Tree

Method 3 – Upside Method 3 – Upside Down Birthday CakeDown Birthday Cake

3. Upside Down Birthday Cake 1. Write the numbers in tier 1 of the cake. 2. pull out the smallest prime number. 3. Repeat each tier until you can not take out a

common prime number. 4. Multiply the prime numbers on the left like GCF

and the numbers at the bottom on the cake to get the LCM

For Video help see YouTube: http://www.youtube.com/watch?v=GD5jLpSsN00

Example in class will be done using same example numbers 6 and 8.

More Examples

Method 3 – Upside Method 3 – Upside Down Birthday CakeDown Birthday Cake

Thanks for stopping by Let’s do some examples using our

assignment problems.

Remember all power points are posted on my website.

This homework assignment can be found on my website also.

Have a Blessed day