Checkbook balance - how?

I know previous balance - check + deposit = current balance, but how do I show the current balance only if there is a dr or cr? I put in the formula all the way down the balance column, then it shows the current balance all the way down the column. Want to just show a balance after each check or deposit. 3 columns

You could try using IF/AND - If both ‘cr’ & ‘dr’ are blank, then make balance blank otherwise calculate the balance…

=IF(AND(‘dr’="",‘cr’=""),"",‘prev bal’ + ‘cr’ - ‘dr’)

Remember, if you accidentally miss a row out, it will not calculate.