## Formula in Excel 2013

### 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.### Hide formulas from appearing in the edit bar

Usually you can view a formula in the Excel cell when cell is selected, but you can protect spreadsheet to
hide formulas in some cells.

### Calculating the difference between two time stamps

Because time stamps are represented as serial numbers, you can subtract the earlier time from the later time
to get the difference.

### Using Solver

Solver tool allows you to specify multiple adjustable cells and constraints on the values that the
adjustable cells can have, generate a solution that maximizes or minimizes a particular worksheet cell,
generate multiple solutions to a problem.

### Goal Seeking

Goal seeking is a useful feature that works in conjunction with your formulas. If you know what a formula
result should be, Excel can tell you which values of one or more input cells you need to produce that
result.

### Calculating the number of work days between two dates

When calculating the difference between two dates, you may want to exclude weekends and holidays.

### Calculating the number of days between two dates

A common type of date calculation determines the number of days between two dates.

### Counting the number of unique values

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

### 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**: