The Proof! tabletop card game is the inspiration behind our free, online Math Puzzle Challenges. Each carefully constructed puzzle consists of a set of nine cards that hides a challenging equation. If you would like, you can create an account to save your progress. Or if you already have an account, you can log in.

281.
Find a Pair of 0's Using All 9 Cards
282.
Find a Triplet of 0's
283.
Find a Quadruplet of 0's
284.
Find a Pair of 1's Using Only Addition and Division
285.
Find Any Pair Greater Than 100 Using Only Subtraction
286.
Find Any Triplet Using Only Addition
287.
Find a Pair of 500,000's
288.
Find 5 Different Pairs Using Exactly 4 Cards Each
289.
Find Two Different Triplets Greater Than 10
290.
Find Any Pair Greater Than 100
291.
Find 2 Different Pairs Using Only Addition
292.
Find Any Pair Greater Than 0 Using All 9 Cards
293.
Find Any Pair Using Subtraction At Least 5 Times
294.
Find 5 Different Pairs Less Than 20
295.
Find 3 Different Triplets
296.
Find a Pair of 143/323's Using Only Multiplication and Division
297.
Find Any Pair Greater Than 0 Using All 9 Cards
298.
Find 11 Different Pairs Using Exactly 3 Cards Each
299.
Find a Pair of 80's
300.
Find 3 Different Triplets