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Learn mathematical concepts, problem-solving techniques, and programming fundamentals
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Explore the full taxonomy and open topic pages (overview + practice problems)
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Interactive Puzzles
Hands-on puzzle resources with interactive simulators and practice problems.
Techniques
Core problem-solving techniques and methods used across mathematics and olympiad competitions.
Interactive Puzzles lessons
Hands-on puzzle resources with interactive simulators and practice problems.
Explore clock-hand angle problems: when the hands overlap, point at right angles, or line up in othe...
Junior
Word puzzles where letters represent digits in arithmetic equations. Each letter stands for a unique...
Junior
Divide grid shapes along the lines between cells into a given number of equal parts, or so that each...
Primary
In competitive games, the best outcome depends not only on your own decisions but also on the choice...
Junior
A classic number puzzle where rows, columns, and diagonals all add up to the same magic sum....
Junior
Classic brain teasers where you transport items or people across a river while following specific ru...
Junior
Classic brain teasers where you measure exact amounts using unmarked containers through filling, emp...
Junior