FINDING COMMONFACTORS and

MULTIPLES

MULTIPLES: The product of any number and a whole number. (Skip counting)

MAKE A LIST OF THE FIRST 10 MULTIPLES FOR EACH NUMBER BELOW:

20:

30:

20, 40, 60, 80, 100, 120, 140, 160, 180, 200

30, 60, 90, 120, 150, 180, 210, 240, 270, 300

Which multiples do both numbers have in common?

We call these, common multiples:

What statement can be made about the number 60?

60 is the Lowest Common Multiple LCM

THINK BACK TO YESTERDAY…

Without looking at your notes, describe to your partner what a factor is.

FACTORS: A number that is multiplied by another number to get a product.

MAKE A LIST OF THE FACTORS FOR EACH NUMBER BELOW:

12:

30:

1, 2, 3, 4, 6, 12

1, 2, 3, 5, 6, 10, 15, 30

WHAT FACTORS DO EACH NUMBER HAVE IN COMMON?What statement can be made about the number 6? 6 is the Greatest Common Factor GCF

We are going to use the idea of common factors or common multiples to solve some problems. How many of you have ever been on one of these?

Before going on a Ferris Wheel, did you ever wonder about the number of trips around you would get?

What about the size of the Ferris Wheel? How does that affect your ride?

For each situation (A-C), the goal is to find out how many seconds will pass before Jeremy and Deborah are both at the bottom again.

A) The large Ferris wheel makes one revolution in 60 seconds. The small Ferris wheel makes one revolution in 20 seconds.

B) The large Ferris wheel makes one revolution in 50 seconds. The small Ferris wheel makes one revolution in 30 seconds.

C) The large Ferris wheel makes one revolution in 20 seconds. The small Ferris wheel makes one revolution in 11 seconds.