Mathematics

Take a free Maths Test every fortnight at
http://free-quiz.4gmat.com/

Proof of Pythagorus Theorem
http://mathforum.org/isaac/problems/pythagthm.html

Beat the Calculator
http://mathforum.org/k12/mathtips/beatcalc.html

Divisibility Rules
http://mathforum.org/k12/mathtips/division.tips.html

See again
http://mathforum.org/k12/mathtips/mathtips.html
http://mathforum.org/isaac/problems/prime1.html