Page 14 - SPARK OF MATH book 6

(1-5) The Greatest Common Factor (GCF).

The Greatest Common Factor (GCF), also called Greatest Common
Divisor (GCD) is the greatest factor shared between two or more
numbers.
To Find GCF of (18, 36), Use prime factorization to find GCF

18 36

2 9 4 9
2 18 2 36
3 3 2 2 3 3 2 18
3 9
18 = 2 x 3 x 3 36 = 2 x 2 x 3 x 3 3 3 3 9

Look at the common factors 1 3 3
1
2x3x3= 18

Determine the Greatest Common Factor of each set of numbers.

6, 24 30, 20
6= 30=
24= 20=
GCF= GCF=

30, 18 6, 22
30= 6=
18= 22=
GCF= GCF=

42, 58 63, 36
42= 63=
58= 36=
GCF= GCF=

Your Work

Find the GCF of 48, 50, 75.

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