To add use the sign. If there is no equals sign then whatever is typed in the cell will not be regarded as a formula. When I copy the cell B1 and paste it in B2 the formula automatically becomes A2A3.
Function is a predefined formula already available in Excel.
SUM is a great basic formula to know especially because it allows you to add up numbers in different ways. First SUM can add up entire rows of numbers or just certain cells within a row. A formula is an expression which calculates the value of a cell. Create a simple formula in Excel On the worksheet click the cell in which you want to enter the formula.