Tipit: an Ad-Free Tip Calculator

1. Enter your bill amount. (0,9999)
2. Tap on "Enter" for the result of 18% as default tip percentage.
3. (Optional) Adjust tip percentage with the slide bar.
4. (Optional) Adjust numbers to split with the "-/+" buttons. [1, 20]
5. Tap on "New Bill" to start a new calculation.
6. Voila!
P.S.: This is my first published app. Advice is always appreciated!