## Formula in Excel 365

### Using Solver

The

**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 difference between two time stamps

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

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

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

### Counting the number of unique values

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

### 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., the sum of values seems incorrect because Excel displays a limited number of decimal places, and their sum is not equal to the real sum.

### How to insert functions into formulas

The easiest way to enter a function into a formula is to use the Excel program's

**Insert Function**dialog box.### Combining text and formatted values

The Excel

**TEXT**function enables you to specify numbers and date format.### Basic Formula operators

Excel formulas support many different operators.

**Operators**are symbols that indicate what mathematical or logical operation a formula should perform. The following are the most common operators used in Excel.### Using the formula bar as a calculator

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

**Formula**bar as a calculator.