University of Cambridge
University of Cambridge: Nrich: Two Stones Game
Sharpen your problem-solving and strategy skills while playing the interactive game, Two Stones. The rules are simple, but the game requires some thinking if you want to beat the computer. Watch as the play proceeds to see what it takes...
University of Cambridge
University of Cambridge: Nrich: Game Counter Roundup
Sharpen your problem solving and strategy skills playing this interactive game, Counter Roundup. The rules are simple but the game requires some thinking if you want to beat the computer. There is a "Get Printable Page," link at the top...
Other
Math Stories: Working Backwards
At this one page site you can work through step by step a sample problem that illustrates the problem solving strategy for "Working backwards." The answer is right there to help you check your thinking.