Finding Greatest Common Factor and
Least Common Multiple using PRIMES

Base 10 Numbers                     Base 2  Numbers                      Deb’s World Numbers

……                                        0 = 0                                        ……..

……..                                      1 = 1                                        © = ©

4 = 2 x 2                                  10 = 10                                    @ = @

5 = 5                                        11 = 11                                    Œ = © x ©

6 = 2 x 6                                  100 = 10 x 10                          Μ = Μ

7 = 7                                        101 = 101                                Σ = © x @

8 = 2 x 4                                  110 = 110                                Δ =  Μ x Σ

9 = 3 X 3                                 111 = 111                                Ώ = Ώ

10 = 2 X 5                               1000 = 10 x 100                      П =  Σ X Σ

………                                    1001 = 11 X 11                       Ж = @ x Δ x П

1010 = 101 x 10                      Д = Ж x Ж x Ж

1011 = 1011                            …………

1100 = 11 x 100         

EXAMPLE: Find the GCF (factor each to primes, line up, circle those that

Are found in both numbers

8 =      2 x 2 x 2               10 =      10                      Δ  = Μ x © x @

12 =    2 x 2 x   3             100 =    10 x 10               Œ  =         © x       ©

GCF= 2 x 2   =   4          GCF =  10                      GCF =     ©                   

 

Factor these numbers into their primes.

1)                                             2)                                             3)

20 =                                1000 =                            П =

16 =                                                                                                   

GCF =                            GCF =                            GCF =

 

4)                                             5)                                             6)

9  =                                1001 =                            Д =

15 =                                1100 =                            Σ  =                     

GCF =                            GCF =                            GCF =

 

7)                                             8)                                             9)

25 =                                100 =                                       @ =

30 =                                1000=                                       Ж =                    

GCF =                            GCF =                            GCF =

 

10)                                           11)                                           12)

30 =                                10 =                                Ж =

18 =                                1010 =                             Δ =                      

GCF =                            GCF =                            GCF =