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Explaining the Divisibility Rules - http://mathforum.org/k12/mathtips/ward.html
Proof of the elementary division rules, plus some lesser-known rules for larger divisors and other bases. |
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Divisibility Criteria - http://www.cut-the-knot.com/blue/divisibility.html
Ways of telling whether one number divides another without actually carrying the division through, constructed here in terms of the digits of the number. |
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Divisibility Tests - http://www.jimloy.com/number/divis.htm
Jim Loy explains the divisibility rules up to 11, including a detailed study of 7. |
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Divisibility War - http://edweb.sdsu.edu/courses/edtec670/Cardboard/card/d/Divisibility.html
A card game to teach divisibility rules. |
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Digital Divisibility Tests - http://www.primepuzzles.net/puzzles/puzz_101.htm
From Carlos Rivera's Prime Puzzles and Problems collection. Carlos asks for the general divisibility rules for any prime number. |