What is Euclid's ladder?

Answer 1

The greatest common factor (GCF), also known as the greatest common divisor (GCD), represents the largest number that divides into each member of a set of numbers. Smaller GCFs can be quickly calculated using the prime factors of each number, but calculating large GCFs the same way is sometimes difficult. An algorithm devised by Euclid, (the ladder) lets you find the GCF of any number without extensive factoring. All you need is the ability to do long division.