I was wondering how Al Khwarizmi's method of multiplication worked? I was hoping for a simple explanation in layman's terms.
For those of you unfamiliar with the method its basically this:
If you have two numbers, x and y, write them beside each other. Then repeat the following: divide the first number (x) by two , rounding the result (if it has a 0.5 if the number was odd) and then double the second number. Keep repeating till the first number is one. Then strike out all the rows where the first number is even, and add up whatever remains in the second column.
i.e. 11 * 13.
2 52 (strike out)
13 + 26 + 104 = 143