Excel formula and mathematics and Modifying a formula in Excel

We showed how to add two values in the example. We used the + sign, which is well known in mathematics. Remaining mathematical operations use the following signs in formulas:
+......................adding
-..............subtraction
*..........multiplication
/......................divide
%.................percents
^.....................power

Demands change over time in every occupation, and we must similarly adapt Excel formulas to meet these demands (calculating expenses, monitoring revenues, tax calculations, etc.).
Example:

Revising a formula directly in the formula bar is the easiest. For example, we would like to add the number 10 to the formula.

Modifynig a formula in Excel step-by-step:

1. We first click on the cell, to which the formula applies, using the mouse – i.e. cell D3. This displays the formula in the formula field.
2. We click on the field and we can modify it using the familiar text cursor that appears. We simply add + 10 to the end of the formula.
3. After revising the formula, we press the Enter key and the revised formula is saved, and the formula in cell D3 is immediately calculated.