1. cálculo   calculus   algebra   physics   psychology   Hint Half-n-half Clue   2. astronomía   history   zoology   astronomy   geology   Half-n-half Clue   3. filosofía   geology   physics   philosophy   chemistry   Half-n-half Clue   4. geografía   zoology   geography   biology   trigonometry   Half-n-half Clue   5. física   psychology   physics   zoology   botany   Half-n-half Clue   6. álgebra   algebra   astronomy   calculus   geology   Half-n-half Clue   7. química   astronomy   physics   chemistry   botany   Half-n-half Clue