anyone good at excell?

i have a spreadsheet in excel im working on, and there is a column which is populated by a formula
the idea is all my monthly expenses are in column A , there is a formula in column E that tells me the remaining expenses in A this month (after that date) and it is based on a figured in column D so i can look at my bank account, punch the balance in on column D (where the number equals the date, so today, i would use D20, and then E20 would tell me how much money i can spend at summit

the formula for E20 is =(D20-A21-A22-A23-A24-A25-A26-A27-A28-A29-A30-A31)

NOW, this leaves me with a long list of negative numbers, all down column E, because column D is generally empty

is there a way to hide the cells in column E unless the corresponding cell in column E is populated?

in other words, i only want to see E20 if i put something in D20