Let's say you want to figure out how much bottled water that you need for a customer conference (total attendees × 4 days × 3 bottles per day) or the reimbursement travel cost for a business trip (total miles × 0.46). There are several ways to multiply numbers.
What do you want to do?
Multiply numbers in a cell
To do this task, use the * (asterisk) arithmetic operator.
For example, if you type =5*10 in a cell, the cell displays the result, 50.
Multiply a column of numbers by a constant number
Suppose you want to multiply each cell in a column of seven numbers by a number that is contained in another cell. In this example, the number you want to multiply by is 3, contained in cell C2.



Type =A2*$C$2 in cell B2. Be sure to include the $ symbol before C and before 2 in the formula.
The $ symbol makes the reference to C2 absolute, which means that when you copy the formula to another cell, the reference will always be to cell C2. If you didn't use $ symbols in the formula and you dragged the formula down to cell B3, Excel would change the formula to =A3*C3, which wouldn't work, because there is no value in C3

Drag the formula in B2 down to the other cells in column B.
Multiply numbers in different cells by using a formula
To do this task, use the asterisk (*) operator or the PRODUCT function.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example

Create a blank workbook or worksheet.

Select the example in the Help topic.
Note: Do not select the row or column headers.
Figure 1: Selecting an example from Help 
Press Ctrl+C.

In the worksheet, select cell A1, and press Ctrl+V.

To switch between viewing the results and viewing the formulas that return the results, press Ctrl+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.


You can use any combination of up to 255 numbers or cell references in the PRODUCT function. For example, the formula =PRODUCT(A2,A4:A15,12,E3:E5,150,G4,H4:J6) multiplies the values in two single cells (A2 and G4), two numbers (12 and 150), and the values in three ranges (A4:A15, E3:E5, and H4:J6).