A computer is an electronic machine that performs input, processing, storing, and output operations according to programmed instructions to carry out specific tasks. Formerly, computers were used primarily to do arithmetic computations. Let’s consider the primitive form of a computer – a calculator. For example, if you need a calculator to perform such an operation as “3+5=”, you input numbers and perform the arithmetic operation. Then the calculator processes arithmetic expression by adding 3 and 5, stores the result - 8, and outputs the result onto the display.