1. COURSE 3 LESSON 4-1
Factors
A band with 36 members is marching with a 32-member band. If the two bands are to have the same number of columns, what is the greatest number of columns in which you could arrange the two bands?
Begin by finding the factors of 36 and 32.
The factors 1, 2, and 4 are common to both numbers.
36: 1, 2, 3, 4, 6, 9, 12, 18, 36
32: 1, 2, 4, 8, 16, 32
The GCF is 4.
36: 1, 2, 3, 4, 6, 9, 12, 18, 36
32: 1, 2, 4, 8, 16, 32
36: 1, 2, 3, 4, 6, 9, 12, 18, 36
32: 1, 2, 4, 8, 16, 32
So, 4 is the greatest number of columns in which you can arrange the bands.
4-1

2. Factors Find the GCF of 55 and 231.
COURSE 3 LESSON 4-1
Factors
Find the GCF of 55 and 231.
Step 1 Find the prime factorization of each number. 55 11 5
231 77 3 7
Step 2 Find the product of the common prime factors of each number.
55 = 5 • 11
231 = 3 • 7 • 11
The only common prime factor is 11. The GCF of 55 and 231 is 11.
4-1