Question

Write all the factors of the given numbers and list their common factors:

i. 12, 16 

ii. 21, 24 

iii. 25, 30 

iv. 24, 25 

v. 56, 72

Answer 1

i. Factors of 12 = 1, 2, 3, 4, 6, 12 

Factors of 16 = 1, 2, 4, 8, 16 

∴ Common factors of 12 and 16 = 1, 2, 4

ii. Factors of 21 = 1, 3, 7, 21 

Factors of 24 = 1, 2, 3, 4, 6, 8, 12, 24 

∴ Common factors of 21 and 24 = 1, 3

iii. Factors of 25 = 1, 5, 25 

Factors of 30 = 1, 2, 3, 5, 6, 10, 15, 30 

∴ Common factors of 25 and 30 = 1, 5

iv. Factors of 24 = 1, 2, 3, 4, 6, 8, 12, 24 

Factors of 25 = 1,5, 25

∴ Common factor of 24 and 25 = 1

v. Factors of 56 = 1, 2, 4, 7, 8, 14, 28, 56 

Factors of 72 = 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72 

∴ Common factors of 56 and 72 = 1, 2, 4, 8