To divide two numbers you need to create a formula since there is no DIVIDE function in Excel.
Important points to remember about Excel formulas:
 Formulas in Excel always begin with the equal sign ( = );
 The equal sign always goes in the cell where you want the answer to go;
 The division symbol is the forward slash ( / );
 The formula is completed by pressing the Enter key on the keyboard.
Using Cell References in Formulas
Although it is possible to enter numbers directly into a formula, it is much better to enter the data into worksheet cells and then use the addresses or references of those cells in the formula as shown in the image above.
By using cell references – such as A1 or C5 – rather than the actual data in a formula, later, if it becomes necessary to change the data, it is a simple matter of replacing the data in the cells rather than rewriting the formula.
Normally, the results of the formula will update automatically once the data changes.
Division Formula Example
As seen in row 2 in the image above, this example creates a formula in cell B2 that divides the data in cell A2 by the data in A3.
The finished formula in cell B2 will be:
= A2/A3
Entering the Data

Type the number 20 in cell A2 and press the Enter key on the keyboard;

Type the number 10 in cell A3 and press the Enter key.
Entering the Formula Using Pointing
Although it is possible to just type the formula
=A2/A3
into cell B2 and have the correct answer of 2 display in that cell, it is better to use pointing to add the cell references to formulas in order to minimize the possibility of errors created by typing in the wrong cell reference.
Pointing involves clicking on the cell containing the data with the mouse pointer to add the cell reference to the formula.
To enter the formula:

Type an equal sign in cell B2 to begin the formula.

Click on cell A2 with the mouse pointer to add that cell reference to the formula after the equal sign.

Type the division sign  the forward slash  ( / ) into cell B2 after the cell reference.

Click on cell A3 with the mouse pointer to add that cell reference to the formula after the division sign;

Press the Enter key on the keyboard to complete the formula;

The answer 2 should be present in cell B2 since 20 divided by 10 is equal to 2;

Even though the answer is seen in cell B2, clicking on that cell will display the formula =A2/A3 in the formula bar above the worksheet.
Changing the Formula Data
To test the value of using cell references in a formula, change the number in cell A3 from 10 to 5 and press the Enter key on the keyboard.
The answer in cell B2 should automatically update to 4 to reflect the change in data in cell A3.
#DIV/O! Formula Errors
The most common error associated with division operations in Excel is the #DIV/O! error value.
This error is displayed when the denominator in the division formula is equal to zero – which is not allowed in ordinary arithmetic.
The most likely reason for this happening is that an incorrect cell reference was entered into the formula or, as shown in row 3 in the image above, the formula was copied to another location using the fill handle and the changing cell references results in the error.
Calculate Percentages With Division Formulas
A percentage is a just a comparison between two numbers that make use of the division operation.
More specifically, it is a fraction or decimal that is calculated by dividing the numerator by the denominator and multiplying the result by 100.
The general form of the equation would be:
= (numerator/denominator)*100
When the results of a division operation – or quotient – is less one, Excel represents it, by default, as a decimal, as shown in row 4, where the numerator is set to 10, the denominator to 20, and the quotient is equal to 0.5.
That result can be changed to a percent by changing the formatting in the cell to percent formatting from the default General format  as shown by the 50% result displayed in cell B5 in the image below.
That cell contains the identical formula as cell B4. The only difference is the formatting on the cell.
In effect, when percent formatting is applied in Excel, the program multiplies the decimal value by 100 and adds the percent symbol.
Creating More Complex Formulas
To expand the formulas in the image to include additional operations  such as multiplication or addition  just continue to add the correct mathematical operator followed by the cell reference containing the new data.
Before mixing different mathematical operations together in a formula, however, it is important to understand the order of operations that Excel follows when evaluating a formula.
For practice, try this step by step example of a more complex formula.