How Does a Computer Calculate Numbers?

Video Transcript

"Hi, my name is Dave Andrews. Today I'm going to talk to you about how a computer calculates numbers. Now the very first thing that you need to know. When you're talking about how computers calculate numbers is that a computer only ever sees a short burst of five watts of electricity. That's all they ever see. For every single operation that they're doing. They don't understand the data that they're working with. All they know is, is there electricity here? Or it there not electricity here? And that is represented in computers by a process called Binary Code. Let's go to our computer. I have a little, a little short list here of some Binary Codes. Now what Binary does is, is it's basically a numbering system. Now I'll highlight the Binary section here. To where, you either have a one or a zero. Now a one, represents a burst of electricity. And a zero means there is no burst of electricity. So if you're calculating a number one. You get a burst right here, at the very beginning. And no other electricity passed that. The computer will interpret that as being a one. And now if you get a burst of electricity on the second bit here. The computer will interpret it as being a two and so on. Now it adds those together. Basically your first row here. Instead of being tens based is based on two. Your first row is one, your second row is two. Your third row is four. And your fourth row is eight. That continues on, basically multiplying by two. Till it gets sixteen, thirty two, sixty four. And a hundred and twenty eight. And the computer adds all those numbers together. And it will come up with a result. For instance, for seven. You have a bit in the one. That will be one. You have a bit in the two. That will be two. And you have a bit in the four. So that will basically amount to four plus two plus one. Which is equal to seven. That's basically how a computer will calculate these numbers. As you can see for the number eight. It has a single burst of electricity in the eights column. And none others. So that computer knows that, that is an eight. If I had this number right here. With an eight and then a one. That will be the number nine. So basically a computer will compare these numbers. See what it has. When it got electricity. And when it did not get electricity. And it will know what number it is currently calculating. My name is Dave Andrews. And I've just told you how computers compute numbers."