What to Know
 Assuming rows in Col A, the basic formula is = A1*A2
 Formulas in Excel begin with an equal sign ( = ), which goes in the cell where you want to display the answer.
 The multiplication sign or operator used in Excel formulas is the asterisk ( * ) symbol.
This article explains multiplication in Excel for versions 2019, 2016, 2013, 2010, Excel Online, and Excel for Mac.
Multiply Rows or Columns: Use Cell References in Formulas
It's possible to enter numbers directly into a formula. But it's much better to enter the data into worksheet cells and then use the addresses or references of those cells in the formula.
The main advantage of using cell references in a formula, rather than the actual data, can be seen when the data in the cells is changed. When the actual data is used for the calculation, the formula needs to be rewritten. When using cell references, the results of the formula update automatically when the data in the target cells change.
Use Pointing to Enter Cell References
It is possible to type the cell references to be used in the formula, but a better approach is to use pointing to add the cell references. Pointing involves selecting the target cells containing the data to add the cell reference to the formula. This minimizes the possibility of errors created by typing the wrong cell reference.
Multiplication Formula
The example in the image above creates a formula in cell C1 that multiplies the data in cell A1 by the data in cell A2. The finished formula in cell E1 looks like: =A1*A2.
Type the Data

Type the number 10 in cell A1 and press Enter.

Type the number 20 in cell A2 and press Enter.
Create the Formula

Select cell C1 to make it the active cell. This is where the result of the formula will appear.

Type = (an equal sign) into cell C1.

Select cell A1 to enter that cell reference into the formula.

Type * (an asterisk symbol) after cell A1.

Select cell A2 to enter that cell reference.

Press Enter to complete the formula. Cell C1 displays the result of 200.
Update the Formula Data
To test the value of using cell references in a formula, change the number in cell A2 from 20 to 5 and press Enter. The answer in cell C1 automatically updates to 50 to reflect the change in data in cell A2.
Fix the Formula
If it becomes necessary to correct or change a formula:
 Doubleclick the formula in the worksheet to place Excel in Edit mode and then make changes to the formula. This works best for minor changes.
 Select the cell containing the formula and rewrite the entire formula. This method is best for major changes.
Create More Complex Formulas
To write more complex formulas that include multiple operations (such as subtraction, addition, and division, as well as multiplication), add the correct mathematical operators in the correct order followed by the cell references containing the data. For practice, try this step by step example of a more complex formula.
Before mixing different mathematical operations together in a formula, it is important to understand the order of operations that Excel follows when evaluating a formula.