Daily UI - Calculator Mockup #004

Hello Dribble users,
This is my #004 work, part of Daily UI project. Calculator mockup, hope you like it.
Don't forget to drop some feedback! #dailyui
Big size here: http://bit.ly/dailyui-1

Notice: I'm not a professional designer, just an amateur. So don't hesitate to give me some tips.
See you soon!