## Formula in Excel 2003

### How to count cells by criteria

Use

**COUNTIF**if you need to sum values for a particular person or other criterion.### How to sum cells by criteria

Use

**SUMIF**if you need to sum values for a particular person or other criterion.### Basic Formula operators

There are several operators that could be used in formulas.

### How to avoid misleading numbers

Applying a number format to a cell doesn't change the value, but only how the value appears in the
worksheet. Formatting can play a joke with you, e.g., sum of values seems incorrect because Excel displays a
limited number of decimal places and their sum is not equal to the real sum.

### Using the formula bar as a calculator

If you simply need to perform a calculation, you can use the

**Formula**bar as a calculator.### Referencing cells outside the worksheet

Formulas can refer to cells in other worksheets-and the worksheets don't even have to be in the same
workbook. Excel uses a special type of notation to handle these types of references.

### Shortcut key to switch between relative, absolute and mixed references

You can enter nonrelative references (absolute or mixed) manually by inserting dollar signs in the
appropriate positions, or you can use a handy shortcut -

**F4**key.### Creating and using named ranges

Range names is a powerful Excel feature which allows you to give a symbolic name for the cell or range of
cells to be later used as convenient replacement for cell/range address in formulas.

### Excel Formula auditing tools

If you would like to better understand how some of these complex array formulas work, consider using a handy
tool -

**Formula Evaluator**:### Counting the number of unique values

You can easily count the number of unique values of the range using a simple formula.