Software bug

A software bug is a problem in the instructions a computer is following, which causes it to do something wrong. A bug can be very small and not cause any problems, or it can be very big and cause the program not to work at all. For example, if a computer is supposed to draw a triangle but instead draws a square, that's a bug. It's like when your Mom tells you to clean your room, but instead you play with your toys - the instructions weren't followed correctly and a mistake was made.