What is GCD(2, 8)?

The GCD (Greatest Common Divisor) is the largest number that can divide two (or more) numbers without leaving a remainder.

The GCD of 2 and 8 is 2.

How to compute GCD(2, 8)

Comparing the divisors of 2 and 8

This first method consists in listing the divisors of the two numbers and then identifying the largest one they have in common.

Divisors of 2:

1, 2

Divisors of 8:

1, 2, 4, 8

We can see from these two lists that the greatest divisor they have in common is: 2

For small numbers, this can be done quickly. However, as numbers increase, the list of potential divisors grows longer, making this method cumbersome and less practical.

Euclid's algorithm

Fortunately, there's a much more efficient method: Euclid's algorithm. It's particularly well-suited to larger numbers. Here's how it works:

  1. Divide 8 by 2. The quotient is 4 and the remainder is 0.
  2. When you reach a remainder of 0, the last divisor (in this case, 2) is the GCD.