Calculations in Microsoft Excel are achieved through formulas. Formulas are entered differently than other data, although you probably won’t notice the difference.
The procedure for working with Excel worksheets and working on paper is basically the same, except that when you work on paper you have to write down the initial values and then manually work through each step of the calculation. In Excel, the initial values are called input values, and you specify the algorithms in a formula to produce a result based on the input values.
A spreadsheet has the advantage of letting you use the calculation scheme you have created over and over again. All you have to do is enter new input values, and the formulas containing the algorithms calculate the result. If you create a table of values, you can perform any number of calculations based on the same rules.
Remember that Excel cannot work directly with algebraic formulas, because the components must refer to real values. Excel also cannot calculate and draw graphs directly from a formula. The values must be calculated in a table.