Given a box of certain dimensions, young mathematicians must determine if a box that is twice as big, actually holds twice as much. This is a brain-teaser of a problem. The worksheet provides a handy table that has learners calculate the...

Whether you're lost at sea, lost in the woods, or testing communication skills, teamwork is always important. Build your middle and high schoolers' cooperative and collaborative skills with four activities that prompts groups to compete...

The brain teasers at this site test "your ability to recognize groups of common attributes" and "to figure out why the words or letters are grouped as they are." Sort brain teasers according to title, popularity, and difficulty, and...

Check out the variety of probability brain teasers at this site, which you can sort by popularity and difficulty.

Check out the variety of math brain teasers at this site, which you can sort by popularity and difficulty.

Test your critical thinking skills with a variety of cryptography brain teasers, phrases or expressions "encoded in some way." Solve the teasers provided at this site, and submit your own for others to try!

Discovery School offers a terrific "categorized archive of challenging Brain Boosters." Choose from hundreds of engaging activities pertaining to Categorization, Lateral Thinking, Reasoning, Logic, Word and Letter Play, Spatial...

Check out the variety of optical illusions provided at this site. Fool your eyes with "Chair or Block," "Angles or E," "Old or Young Woman," "Face or Vase," and others.

Educational publisher Houghton Mifflin provides a colorful, engaging site that offers test-prep practice, test-taking strategies, and brain teasers on a variety of math concepts for grades 1-6. Just "Choose an activity and pick a grade,"...

Educational publisher Houghton Mifflin provides a colorful, engaging site that offers test-prep practice, test-taking strategies, and brain teasers on a variety of math concepts for grades 1-6. Just "Choose an activity and pick a grade,"...

The letter equations at this site test your critical thinking skills as well as your knowledge of facts dealing with a variety of subjects: geography, music, history and more.

Six logical problems are defined to challenge students to use critical thinking skills as they tackle these brain-teasers. No answers are provided, but there are some instructions for how to approach the problems.

This site from the Math Forum of Drexel University provides a selection of math puzzles for grades K through 12 are found here. Types include: taking the numbers in the year 2004 and arriving at the numbers 1 through 100, using four 4s...

A storehouse of puzzles designed to train the brain to think in atypical ways. Find riddles, visual puzzles, analogies, math problems, and more. Excellent source of raw material for practicing original and creative thinking one puzzle at...

A realistic world problem using the knowledge of chords and the parts of a circle to solve. Test your knowledge on this brain teaser!

Students, teachers, and parents alike will enjoy this challenging math site. It contains a clever brain teaser section plus creative problems related to algebra, geometry, measurement, numbers, statistics, and probability. A Spanish...

The famous Clockenheimer Cuckoo is missing from Clockenheimer Clocks on Main Street! Help Math Maven get it back by solving a math riddle.

NCTM offers sections on Families & School, Families & Math, Families & Homework, and more. Has links to brain-teaser problems ranging in skill from very easy to challenging. Click Take a Challenge or Challenge Index for...

NOVA explores the basic principle of buoyancy. Also included at this site are some interesting brain-teasers related to the topic.

Find more than 500 "mental calculation tricks" that will help you square numbers, add, multiply divide, subtract, and find percentages. A great resource for advance math students, gifted children, and teachers wanting to find ideas for...

[Free Registration/Login Required] This site provides several word puzzles for students. When given sets of phrases, students will find four-letter words hidden within each set.