Computers are hard-coded to read certain patterns of 1’s and 0’s as instructions to turn certain switches on or off. So a specific pattern might turn on the switch to the addition circuit and turn off the switch to the other circuits, allowing the computer to perform addition on some numbers.
This works because 1’s and 0’s are just voltage levels, and the switches inside a computer are voltage-controlled switches.
Computer makers have a list of what patterns you should use in order to turn on which circuits. They then use that list to create higher level programming languages using words that humans can more easily program in. But at the end of the day, those words get translated into the 1’s and 0’s needed to turn on the desired circuit.
Latest Answers