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.
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*$B$2 in a new column in your spreadsheet (the above example uses column D). Be sure to include a $ symbol before B and before 2 in the formula, and press ENTER.
Note: Using $ symbols tells Excel that the reference to B2 is "absolute," which means that when you copy the formula to another cell, the reference will always be to cell B2. 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 B3.

Drag the formula down to the other cells in the column.
Note: In Excel 2016, the cells are populated automatically.
Multiply numbers in different cells by using a formula
You can use the PRODUCT function to multiply numbers, cells, and ranges.
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 two single cells (A2 and G4), two numbers (12 and 150), and three ranges (A4:A15, E3:E5, and H4:J6).