To return a zero when a referenced cell is blank in Excel, you can use the IF function in combination with the ISBLANK function. Here are the steps:
Select the cell where you want the result to appear.
Type the following formula: =IF(ISBLANK(reference cell),0,reference cell)
Replace "reference cell" with the cell that you want to check if it's blank. For example, if you want to check if cell A1 is blank, you would replace "reference cell" with "A1".
Press Enter to complete the formula.
The IF function checks if the referenced cell is blank using the ISBLANK function. If the referenced cell is blank, the formula returns a zero. If the referenced cell is not blank, the formula returns the value of the referenced cell.
For example, if cell A1 contains the value "100", and you want to return a zero if it's blank, you would use the formula: =IF(ISBLANK(A1),0,A1). If A1 is blank, the formula will return 0. If A1 contains a value, the formula will return that value.