The Euclidean Algorithm is an algorithm that can calculate the greatest common divisor (GCD)/highest common factor (HCF) efficiently. It's even used in questions like... 'What is the size of the largest square tile that can cover a room of length and width?' Think of it like you have a rectangle. You start filling it up using the biggest square tiles that fit the rectangle until you cannot fill it up anymore. Now there is a small gap, and you start filling that up with the biggest square tiles that can fit until you can't. You repeat this until the whole rectangle has been filled. The last size of the last square you used is the GCD. That is how the Euclidean Algorithm works. To be added: Visual representation of what is happening
