IF function is a very useful and most widely used conditional function in excel this function is used to give a result based on certain criteria. The ROUND formula in the Excel dialogue box will open as shown below. When you create a formula that contains a function you can use the Insert Function dialog box to help you enter worksheet functions.
If TRUE the IF function returns the sum of Data2 if FALSE the IF function returns 0.
For example SUM55 sums all values in the 5th row. The function will determine if any of the conditions in a test is TRUE. The AND function can be used as the logical test inside the IF function to avoid extra nested IFs and can be combined with the OR function. To sum a range of cells use the SUM function see second image on this page.