# Multiplying Numbers Using the Binary System

Apr 29, 2008 | binary, Engineering, math

Hello, Sprechen Sie Talk? I am Martin Rudloff and welcome to my corner! Today's technical (mathematical?) tidbit is about multiplying numbers using the binary system. It's actually easier than you may think!

Let's multiply two numbers: 130 x 5, for example!

1. First, write down the two numbers you want to multiply side by side: 130 x 5.
• Now, start to create a column under the number 130. Start with the number 1 and keep doubling it until you reach a number under 130. In our example you would have created a column with 8 numbers under 130: 1, 2, 4, 8, 16, 32, 64, and 128.
• Now, let's create a column under the number 5. Start with 5 and keep doubling it until you have the same amount of numbers as in column 1. In our example, you would have created a column with 8 numbers: 5, 10, 20, 40, 80, 160, 320, and 640 (a total of 8 numbers).
• In the first column, circle all numbers that add up to 130. In this example that would be 2 and 128 (2 + 128 = 130)
• In the second column, circle all numbers that correspond to those circled in the first column. In this example that would be 10 and 640.
• Add the numbers circled from the second column and you will get the answer to the equation: 130 x 5 = 650 (10 + 640 = 650) 