Finding the greatest common factor
01252013, 05:05 PM


Just like addends are the numbers you add together to get a sum, factors are the numbers you can multiply together to get a product. Every number has at least two factors: the number itself and one:
7: 1, 7 Numbers with only those two factors are called prime numbers. 3, 5, 7, 11, 13, 17, 19 are some prime numbers.
Some examples of numbers with more factors:
12: 1, 2, 3,4,6, 12
20: 1, 2, 4, 5, 10, 20
15: 1, 3, 5, 15
I would do many examples like these on the board and then give them some examples to do on their own:
8: __ __ __ __
36: __ __ __ __ __ __ __ __ __
After they have shown that they can do this, it's time to give them some numbers to find the largest common multiple for.
9: 1, 3, 9
15: 1, 3, 5, 15 3 is the largest common multiple
28: __ __ __ __ __ __
42: __ __ __ __ __ __ __ __ This is a good example of another
they could be given.
