### 1.2. Addition and Subtraction

Now that we have refreshed our memory about the different kinds of numbers, let's see how they are used in the various arithmetic operations. We will start with addition and subtraction.

#### 1.2.1. Adding and Subtracting Integers by Calculator

There are many types of calculators in use. In this text we will show screens for the TI-83 Plus calculator, which will usually be the same for the TI-84 Plus, and for TI-89 Titanium, which we shall indicate simply as TI-89.

To add two numbers by calculator, simply enter the first number; press ; enter the second number; and press the enter key or the equals key , or the execute key , depending upon your particular calculator. The number we get is called the sum of the two numbers.

For subtraction we use the key (not the key). The result is called the difference of the two numbers.

TI-83/84 screen for Example 16. Your ...