I'm using some numbers fields to do some basic math based on a user submission in the first number field. Two questions:

1. Can I make the calculation fields empty until the first field is filled in? As it is, they show weird numbers based on the math that are completely irrelevant.

2. Since the numbers represent money, is there a way to force two decimal places even when the hundredths place is zero? I want 2.50 to show as 2.50, not 2.5.

Thanks!