Formula If. Otherwise the expression evaluates to false. If the value in one row of the column quarter1 is equal to 100 the expression evaluates to true.
So the formula in e2 is saying if actual is greater than budgeted then subtract the budgeted amount from the actual amount otherwise return nothing. If true do one thing if false do another. You can always use the evaluate formula tool to step through your if formula.
On the formulas tab in the formula auditing group click evaluate formula.
For example quarter1 100 is a logical expression. So you use the or function to check both conditions and if the result is true decrease the total amount by 10 b2 c2 0 9 otherwise return the full price b2 c2. As a worksheet function the if function can be entered as part of a formula in a cell of a worksheet. For example quarter1 100 is a logical expression.