When using formulas in Excel you can add, subtract, multiply, and divide. Use simple Excel formulas to also make cell references in Excel.
What if a column contains many numbers, each of which regularly changes? You don't want to write a new formula each time a number is changed. Luckily, Excel 2003 lets you include cell references in formulas.
A formula can add the value of two cells—B2 and B3, for example. Type any two values in these two cells, and the formula will adjust the answer accordingly.
Using this method to calculate two numbers—128 and 345, for example—requires that you type 128 in cell B2, for example, and 345 in cell B3. The Excel formula, =B2+B3, would then be defined in cell B4.