Excel formulas like SUM, AVERAGE, and COUNT, are essential for automating calculations, making data analysis faster and more accurate. 

Create a formula that refers to values in other cells:

1. Select a cell.

2. Type the equal sign = to begin a formula.

3. Click on another cell, or type its address in the selected cell.

4. Enter an operator. For example, – for subtraction.

5. Select the next cell, or type its address in the selected cell.

6. Press Enter. The result of the calculation appears in the cell with the formula.

Enter a formula that contains a built-in function:

1. Select an empty cell.

2. Type an equal sign = and then type a function. For example, =SUM for getting the total sales.

3. Type an opening parenthesis ( to select the list of cells to include.

4. Select the range of cells, and then type a closing parenthesis ) to close list.