Question

What is the greatest common divisor of 20 and 36?

Answer 1

Greatest Common Divisor is `4`.

Explanation:

Divisors of `20` are `{1,2,color(magenta)(4),5,10,20}`

Divisors of `36` are `{1,2,3,color(magenta)(4),6,9,12,18,36}`

Common divisors are `{1,2,color(magenta)(4)}`

And Greatest Common Divisor is `4`.

Answer 2

`2xx2=4`

Explanation:

Writing a number as the product of its prime factors is a very useful method with many applications, especially for large numbers.

Once you have the product of the prime factors, you know everything about that number - whether it is odd, even, a square, a cube or any other power. You can also find all of its composite factors by combining the prime factors in different ways.

`20 = color(red)(2xx2)xxcolor(white)(3xx3)5`
`36 = color(red)(2xx2)xx3xx3`

GCD = `color(red)(2xx2) = 4`