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. This is a hand-picked selection of our math games that focus specifically on subtraction. If you would like, you can create an account to save your progress. Or if you already have an account, you can log in.

1.
Find a Pair of 6's
4.
Find Any Triplet Using At Least 6 Cards
5.
Find a Triplet of 7's Using At Least 7 Cards
7.
Find Any Triplet of Fractions
8.
Find Any Pair Less Than 0
10.
Find 9 Different Pairs Using Exactly 3 Cards Each
11.
Find 4 Different Triplets
13.
Find Any Pair Using All 9 Cards
15.
Find Any Triplet Less Than 0
16.
Find Any Pair Using Only Subtraction
18.
Find Any Pair Using At Least 3 Square Roots
19.
Find Any Pair Using the 6, 27, and 74 Cards
21.
Find 10 Different Quadruplets Less Than 10
23.
Find Any Quintuplet
24.
Find Any Pair Greater Than 0 Using Exactly 8 Cards
25.
Find a Pair of 44's
26.
Find 6 Different Pairs Less Than 20 Using Exactly 3 Cards each
30.
Find Any Pair Greater Than 0 Using All 9 Cards
36.
Find Any Pair Greater Than 0 Using All 9 Cards
38.
Find 14 Different Pairs Greater Than 0 Using Exactly 3 Cards Each