# Excel math: Basic mathematical operations

Using Excel, you want to carry out some basic mathematical calculations. In particular, you want to add, subtract or multiply certain values.

In this learning module “Excel math”, you will discover how to carry out basic mathematical operations in an Excel spreadsheet and some things you should keep in mind when doing so.

HOW DOES EXCEL MATH WORK?

To add together the values of two cells, click first on the cell that you want to contain the result (cell B5 in the example below). Then enter an equal sign (=). Excel switches to display mode. Now click the cell with the first argument (B3) and type a plus sign. Finally, click the cell with the second argument (B4). In this example, the formula =B3+B4 is now visible in the results cell.

As soon as you press [Enter], the sum of the two argument cells will be displayed in the results cell.

Excel math: HINT (1)

If at some time in the future you no longer remember which formula is responsible for a particular result, simply click on the cell that contains the result. The formula behind the result will be displayed in the formula bar.

The formula you use for your caluclation may include not only cell references, but also plain numbers.

In the following example, the annual rent expense is to be calculated in cell B6. First you must click on cell B6 and then enter an equal sign. Excel switches to display mode. Now transfer a reference to the cell that contains the monthly expense into the formula you are building by clicking on cell B5. Next, you can enter a multiplication sign (*) followed by the number “12″, as there are 12 months in the year. When you press [Enter], the calculated result will appear in cell B6.

Excel Math: HINT (2)

You should only work with plain numbers in a formula if you are quite certain that you will remember what the numbers stand for later. It is quite clear, for example, that the number “12″ unmistakably means the 12 months of a year. In general, however, it is better to enter each number involved in a calcualtion into its own cell and to provide such cells with a meaningful lable in a neighboring cell. Then, using the display mode, you can enter references to those cells into your formula. In this way, no matter how much time elapses, you can always be sure of what the various operands in your formula really mean.
The next illustration indicates how NOT to build a formula. Using plain numbers like this, you will soon forget the meaning of each number:

Here, however, the same calculation is made using references to cells that contain the values of interest:

Using the second method, there is no danger of your forgetting what each value means. Besides that, if you alter any of the values, the formula will automatically recalculate, thus always displaying the correct and current result.