This is the 4-bit calculator that I made.

The previous version:
www.planetminecraft.com/project/simple-adding-calculator/

Features: 
-Fast calculating
-Night friendly
-Not so laggy for lower grade computer
-Decimal to binary converter, 4-bit adder, binary to decimal converter and 7 segment display 

Warning:
-Press the button once
-Press one button on each row
-Don't claim this as your own creation