# Enter and Evaluate Expressions on the TI-83 Plus

Arithmetic expressions are evaluated on the TI-83 Plus Home screen. The Home screen is the screen you see when you turn the calculator on. If the Home screen is not already displayed on the calculator, press **[2nd][MODE]** to display it. If you want to clear the contents of the Home screen, repeatedly press **[CLEAR]** until the screen is empty.

Arithmetic expressions are entered in the calculator the same way you would write them on paper if you were restricted to using the division sign (/) for fractional notation. This restriction sometimes requires parentheses around the numerator or the denominator, as illustrated in the first two calculations.

There is a major difference between the subtraction **[–]** key and the **[(-)]** negation key. They are not the same, nor are they interchangeable. Use the **[–]** key to indicate subtraction; use the **[(-)]** key before a number to identify that number as negative.

If you improperly use **[(-)]** to indicate a subtraction problem, or if you improperly use **[–]** to indicate that a number is negative, you get the ERR: SYNTAX error message. The use of these two symbols is illustrated in the last calculation.

When entering numbers, do not use commas. For example, the number 1,000,000 is entered in the calculator as 1000000.

After entering the expression, press **[ENTER]** to evaluate it. The calculator displays the answer on the right side of the next line.