In: Computer Science
Problem 1. Using prime factorization, find gcd(900, 140) and lcm(900, 140).
Prime factorization of 900 = 2 x 2 x 3 x 3 x 5 x
5
Prime factorization of 140 = 2 x 2 x 5 x 7
To find the GCD, find any prime factors that are in common
between the products. Each product contains two 2s and one 5, so
use these for the GCD.
-> GCD = 2 x
2 x 5 = 20
mark all the numbers of products that are used in
GCD
Prime factorization of 900 = 2 x 2 x
3 x 3 x 5 x 5
Prime factorization of 140 = 2 x 2 x
5 x 7
To find the LCM, multiply the GCD by all the numbers in the
products that have not marked (red).
-> LCM = 20 x 3 x 3 x 5
x 7 = 6300