The algorithm is the base of computer programming. Therefore, is necessary to have a good understanding of the concept and elements that featuring an algorithm. The use of the algorithms is ancient and history shows that algorithms were used by Babylonian Mathematicians, about 2500 BC (more about). In the 50s, the word algorithm was most frequently associated with Euclid’s algorithm, a process for finding the greatest common divisor of the two numbers. Given two positive integers m and n, find the GCD Greatest Common Divisor. This means to find the largest positive integer that evenly divides m and n (Knuth, 1997). Let’s to the Classical GCD Excercise. How about sketching an algorithm to represent the GCD exercise and then implement it in the language of your choice? Remark, an algorithm must have Finiteness, Definiteness, Input, Output, and Effectiveness.