304 How long will it take Marie to saw another board into 3 pieces? 289 Are there real-life relations which are symmetric and reflexive but not transitive? 78 Using proof by contradiction vs proof of the contrapositive 70 Fun but serious mathematics books to gift advanced undergraduates. 58 What would base $1$ be?

### Reputation (198,667)

 +10 Area of a parallelogram, vertices $(-1,-1), (4,1), (5,3), (10,5)$. +10 Intersection of 2 subgroups must be a subgroup proof. +10 Symbol for “such that” (not in set) +10 which vectors are perpendicular to each other?

### Questions (2)

 35 Book/tutorial recommendations: acquiring math-oriented reading proficiency in German 8 Bridging any “gaps” between AP Calculus and College/Univ level Calculus II

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 3k calculus × 853 1k elementary-set-theory × 300 2k logic × 604 1k group-theory × 297 2k algebra-precalculus × 503 1k discrete-mathematics × 351 2k abstract-algebra × 324 1k propositional-calculus × 285 2k integration × 391 1k linear-algebra × 252

### Bookmarks (101)

 256 Too old to start math [closed] 244 Fun but serious mathematics books to gift advanced undergraduates. 196 How do I sell out with abstract algebra? 192 Books on Number Theory for Layman [closed] 144 Are there real-life relations which are symmetric and reflexive but not transitive?