THE PYTHAGOREAN PROPERTY. SQUARE ROOT

A central processing unit (CPU) is an important part of almost every computer. The CPU sends signals to control the other parts of the computer, almost like how a brain controls a body.

The CPU is an electronic machine that works on a list of things to do, called 'instructions'. It reads the list of instructions, one instruction at a time, and does each one in order. A list of instructions that a CPU can read is a computer program. A machine that can perform the job of a CPU is often called a Turing machine by mathematicians.

A computer mouse is an input device that is most often used with a personal computer. Moving a mouse along a flat surface can move the on-screen cursor to different items on the screen. Items can be moved or selected by pressing the mouse buttons (called clicking).

It is called a computer mouse because of the wire that connects the mouse to the computer. The people who designed the first computer mice thought that it looked like the tail on a mouse. Today, many computer mice use wireless technology and have no wire.

The motherboard or mainboard is the main circuit board in a complex electronic system, like a computer. It is the most 'central' part of a computer. All of the different parts of the computer are connected to the motherboard. This lets them work together. In most computers, the motherboard is a big green board, but many come in different colours like black, red and yellow.

A computer monitor is an electronic device that shows pictures. Monitors often look similar to televisions. The main difference between a monitor and a television is that a monitor does not have a television tuner to change channels. Monitors often have higher display resolution than televisions. A high display resolution makes it easier to see smaller letters and fine graphics.