University of Cambridge
University of Cambridge: Nrich: Three by Three
Push your problem-solving skills to the limit. Arrange 3 red, 3 blue and 3 yellow counters into a three-by-three square grid, so that there is only one of each color in every row and every column.
University of Cambridge
University of Cambridge: Nrich: Big Dog, Little Dog
On this one page website sharpen your logic and problem solving skills while working on this challenge. The solution is available to double check your solution.
University of Cambridge
University of Cambridge: Nrich: Spiders and Flies
On this one page website sharpen your logic and problem solving skills while working on this challenge. The solution is available to double check your solution.
University of Cambridge
University of Cambridge: Nrich: Fair Exchange?
On this one page website from the University of Cambridge, you can sharpen your problem solving skills while you figure out equivalent values for the amounts shown. The solutions appear on the interactive machine.
University of Cambridge
University of Cambridge: Nrich: Single Track
See if you can figure out how to get two trains on a single track past each other using only a very short siding. Check your results right on this one page websites to see if your answer works.
University of Cambridge
University of Cambridge: Nrich: Two Dots
Sharpen your problem-solving skills with this challenge that has you place dots on a diagram so that only two are on each straight line.
University of Cambridge
University of Cambridge: Nrich: 6 Beads
Use the diagram on this one page website to solve the problem. There are teacher notes and the solution is only a click away.
Other
Math Stories: Draw a Picture
At this one page site you can work through step by step a sample problem that illustrates the problem solving strategy for "Draw a picture." The answer is right there to help you check your thinking.