Excel: How to use formulas?

A formula is an equation that performs operations on worksheet data. Formulas can perform mathematical operations, such as addition and multiplication, or they can compare worksheet values or join text. You DO NOT type in the numbers you are looking for; you type in the equation which will be updated upon the change or entry of any data that is referenced in the equation. Let's have a look at the following sheet first:

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     A       B                C
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1         Mortgage Calculation
2                
3          Loan            12,000.00
4          Interest            9.60%
5          No. of Payment         60
6
7          Monthly Payment:  $252.61
8          
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In the above example, the total amount was $252.61. This amount was NOT typed directly into the cell. Instead, the formula that was typed into the spreadsheet was:

=PMT(C4/12,C5,-C3)

C4 (annual interest rate) was divided by 12 because there are 12 months in a year. Dividing by 12 will give us the interest rate for the payment period - in this case a payment period of one month. It is also important to type in the reference to the constants instead of the constants. If =PMT(.096/12,60,-12000) was entered, the formula would only work for that particular set of data. So if you change the months above, the payment will not be changed. Remember to enter the cell where the data is stored and NOT the data itself.

Formulas are mathematical equations. There is a list of the functions available within Excel under the menu INSERT down to Function. Formulas OR Functions MUST BEGIN with an equal sign (=).