It would be nice to have small calculator in the split bill menu. You could type 4+3.5+2.1+0.5-5 and app would calculate it for you.
And/or
It would be nice to have a slider for easier splitting (if there are only 2 people on a bill)
And
If I there is only two people on a split and I enter the number in “You” field app should calculate the rest of the sum for the partner.