Eli5: Computers can calculate based on instructions. But how do you teach computers what does it mean to add something, multiply, divide, or perform any other operation?

Question

Edit: Most of the answers here are wonderful and spot on.

For those who interpreted it differently due to my incorrect and brief phrasing, by ‘teaching’ I meant how does the computer get to know what it has to do when we want it to perform arithmetic operations (upon seeing the operators)?

And how does it do it? Like how does it ‘add’ stuff the same way humans do and give results which make sense to us mathematically? What exactly is going on inside?

Thanks for all the helpful explanations on programming, switches, circuits, logic gates, and the links!

In: 583

Answer 1

Check out the game Dr. NIM

This game seems like it is thinking but it instead just clever levers that use gravity to flip some see-saws around.

Inside a computer we make electricity to flip some bits, then like the pully analogy mentioned here we make something greater than the whole.

Try out Minecraft and learn about an AND gate, then learn about a D-FlipFlop. You are now on your way to understanding first hand how computers are made.