Use Excel if statement based on the VALUE OF THE CALCULATION of another cell instead of the contents of that cell

I was wondering if there was an easy way to pass the value of a calculation to another function, for instance the if statement.

Lets say I have Cell A1 = 10 and cell A2 = -100

Based on that I have cell A3 = [A1]+[A2] The resulting value of this formula is obviously -90

Now I want Cell A4 to be an if statement on that value, for instance in A4 I put

=IF(A3<0,50, else "")

Basically I want to make A4 = 50 wherever the calculation in A3 is negative, otherwise, leave it blank.

The problem that i find is that Excel sees that there is a formula there, so the cell contents are not less than zero, even though the value of the formula of that cell is.