3.1 Addition and Subtraction
One of the most important advantages of the decimal number system is that calculations can be carried out easily as everything is based on the number ten. This section briefly considers the fundamental operations of addition (+) and subtraction (–) and shows how they can be used in tackling problems. Although you will be using your calculator for a lot of calculations, there will be occasions when it is useful either to work out an answer to a calculation on paper or to carry out a quick calculation in your head. If you are confident in your addition and subtraction skills, then skip this section and go on to the next.