Stage: 4 Challenge Level: 
What remainders do you get when square numbers are divided by
4?
Divisibility. Circles. Long problems. Modulus arithmetic. Stage 5 needs dealing with. Number theory. Mathematical reasoning & proof. Index notation/Indices. Pythagoras' theorem. Stage 5 - Reviewed 2012.
Published May 1999,November 2008,December 2008.
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