Apple Numbers '08 - Manual (Page 94)

94 Chapter 5 Using Formulas and Functions in Tables
To view error and warning messages:
m Click the icon.
A message window summarizes each error and warning condition associated with the
cell.
To have Numbers issue a warning when a cell referenced in a formula is empty, choose
Numbers > Preferences and in the General pane select “Show warnings when formulas
reference empty cells.”
Using Operators
Use operators in formulas to perform arithmetic operations and compare values:
 Arithmetic operators perform arithmetic operations, such as addition and subtraction,
and return numerical results.
 Comparison operators compare two values and return TRUE or FALSE.
Performing Arithmetic Operations
To create a formula that performs an arithmetic operation, you use arithmetic
operators. For example, to add three values in a column, you could create a formula
that looks like this: A2 + A3 + A5.
Here are the basic arithmetic operators. For complete information about arithmetic
operators that Numbers supports, see “Understanding the Arithmetic Operators” on
page 95.
To add an arithmetic formula to a cell:
1 Select an empty cell for displaying the results of the formula.
2 Open the Formula Editor. For example, type an equal sign (=).
3 Enter the formula in the text field following the equal sign.
For example, to enter the formula A3 * B5 + B6, in the text field following the equal
sign you could click or type A3, type * (the multiplication operator), click or type B5,
and then click B6 (if you don’t type an operator before clicking, Numbers adds the plus
sign (+) automatically when you’re not specifying function arguments).
4 Click the Accept button or press Return or Enter to save the formula.
To perform this operation Use this arithmetic operator For example
Sum two values + A2 + B2
Subtract one value from another
value – A2 – B2
Multiply two values * A2 * B2
Divide one value by another
value / A2 / B2