Problem Statement

Explicitly implement   long multiplication.
This is one possible approach to arbitrary-precision integer algebra.

For output, display the result of   264 * 264. Optionally, verify your result against builtin arbitrary precision support. The decimal representation of   264   is: The output of   264 * 264   is   2128,   and is:

Let's start with the solution:

> let X = 2I ** 64 * 2I ** 64 ;;

val X : System.Numerics.BigInteger = 340282366920938463463374607431768211456