University of Cambridge
University of Cambridge: Nrich: Seven Sticks
On this one page website sharpen your logic, triangle properties, and pattern recognition skills while working on this challenge. The solution is available to double check your solution.
Other
Sudoku Puzzles
This site offers many uses for Sudoku, including free online puzzles, free puzzles for school publication, and it gives the history of Sudoku.
Oswego City School District
Regents Exam Prep Center: Working With Logic
Test your logic and knowledge of conditionals, biconditionals, negations, conjunctions, and disjunctions in this twelve-question quiz. Answer each question on your own, then see what the answer and the reasoning behind the answer are.
National Council of Teachers of Mathematics
Nctm: Figure This: Tan, Don't Burn
How about a math challenge for a sunny day at the beach? Apply your problem solving, number sense, and logical reasoning skills to find out how long it would take Helix to get sunburned using SPF 10 lotion. Discover why understanding...
National Council of Teachers of Mathematics
Nctm: Figure This: Keeping Cool
Is it better to by block ice or crushed ice? Use your logical reasoning and measurement skills to solve this challenge that compares surface area of block ice and the same block cut into three cubes. A one page activity from the NCTM...
National Council of Teachers of Mathematics
Nctm: Figure This: Pigeonhole Principle
What is the possibility that another student in your school will have your exact same initials? Try this math challenge using logical reasoning and the "Pigeonhole principle," to discover how this could actually happen. An engaging...
Education Place
Houghton Mifflin: Eduplace: Justifying Answers
Justifying answers, easy enough to an adult, can be difficult for a child. This is a great place to help you teach the concept of "reasonableness" of an answer. There are sections covering lesson plans, tips & tricks, and...
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.