A multiplication algorithm is an algorithm (or method) to multiply two numbers. Depending on the size of the numbers, different algorithms are in use. Efficient multiplication algorithms have existed since the advent of the decimal system.
Read more about Multiplication Algorithm: Grid Method, Long Multiplication, Lattice Multiplication, Peasant or Binary Multiplication, Shift and Add, Quarter Square Multiplication, Fast Multiplication Algorithms For Large Inputs, Lower Bounds, Polynomial Multiplication