Download - Intro to Algebra/Geometry
Intro to Algebra/Geometry
Least Common Multiple
Multiple
The product of any number and an integer
The Multiples of 2:2x1=2, 2x2=4, 2x3=6, 2x4=8, 2x5=10, …
Common
To say that things have something in common we mean that they share the same thing. When we say multiples are common then they have the same multiples.
Multiples of 2:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, . . .
Multiples of 3:3, 6, 9, 12, 15, 18, 21, 24, . . .
Least Common Multiple
The least common multiple (LCM) of two numbers is the smallest number (not zero) that is a multiple of both.
Multiples of 3:3, 6, 9, 12, 15, 18, 21, 24, 27, . . .
Multiples of 4:4, 8, 12, 16, 20, 24, 28, . . .
The LCM of 3 and 4 is 12
Find the LCM
1. 4 and 5
2. 4 and 8
3. 3 and 8
Make a Factor Tree
You can rewrite Numbers as a Product of Prime Numbers by using a Factor Tree.
Finding the LCM using the Factor Tree
1. Write out the Numbers as a product of Prime Factors (ex. 18 = 2 x 3 x 3)
2. Use every factor that is available and use the most possible
3. Multiply the factors together
Use the Product of Primes to Find LCM
35: 7 x 545: 3 x 3 x 5
LCM: 3 x 3 x 5 x 7 = 315
Find LCM using the Product of Primes
1. 6 and 8
2. 7 and 24
3. 33 and 4