Type a plus sign then use your pointer to select C2 to enter the second cell reference into the formula. Hold the left click of the mouse drag the mouse down to the end of the page. If there is no equals sign then whatever is typed in the cell will not be regarded as a formula.
In the Insert Function dialogue box select Math Trig and under the Select a function drop-down menu select SUM and press OK.
Also learn how to work with exponents and basic mathematical functions. To trigger Excel into translating content into a mathematical function you must add an equal sign at the beginning of the cells content. Create a simple formula in Excel. After you insert the equation the Equation Tools Design tab opens with symbols and structures that can be added to your equation.