Question

 You could get 50-75  points!!!!!!

Answer 1

Any number in between -21 and -20 would suffice in this case. If there are no other conditions, let's claim that Stan's bank account balance is -20.75

Answer 2

Thanks for the points. We need gracious people like you.

Less than -20 but greater than -21

One possible answer is =  -20.50.

=  -$20.50

That's a possible balance for Stan's bank account account.

The key here is that for negative numbers, the smaller numbers are bigger than the big numbers. 

E.g  -2  is bigger than -3.