Example questions:
Simple calculator
Java Calculator
Console calculator
Ruby Kata Gem: Calculator
Calculator - C++ operator-overloading
Small Python calculator
Calculator using class templates
Shortening calculator project code
Simple Java calculator
String calculator kata
String calculator in F#
Basic android calculator
Basic calculator in jQuery
Calculator Android App
Refactoring a String Calculator
Calculator with simple input
Basic C# calculator (+,-,*,/) - V2
Basic C# calculator (+,-,*,/)
Much like hangman, tic-tac-toe, or number-guessing-game, calculators are one of the first things one may be asked to program in order to learn a language. I think it would be helpful to have a tag for the many calculators.
So, how about calculator?