With updates on problems solved. Each problem has a symbol indicating the stage, which tells you how little or how much mathematics you need to know to solve the problem but is no indication of its difficulty. Both the puzzles and their solutions are given. You can browse through the puzzles and click on the Solution link to see the solution of the puzzle. Puzzles are categorized by subject area and include solutions compiled from various sources and supposed to be definitive.
Students then revisit the activity, look for patterns, and write the answer algebraically.
On the three lefthand stones, facing the center, stand three of the people. The other three people stand on the three righthand stones, also facing the center. The center stone is not occupied. Everyone must move so that the people originally standing on the righthand stepping stones are on the lefthand stones, and those originally standing on the lefthand stepping stones are on the righthand stones, with the center stone again unoccupied. A teacher lesson plan is provided.