Stage: 3 Challenge Level: 
What happens to multiples of 5 when they are doubled?
What about numbers that are 1 more, 2 more, 3 more and 4 more than a multiple of 5?
What happens to multiples of 5 when 5 is subtracted from them?
What about numbers that are 1 more, 2 more, 3 more and 4 more than a multiple of 5?
What about numbers that are 1 more, 2 more, 3 more and 4 more than a multiple of 5?
What happens to multiples of 5 when 5 is subtracted from them?
What about numbers that are 1 more, 2 more, 3 more and 4 more than a multiple of 5?
Mathematical reasoning & proof. Featured Stage 3&4 Students. Working systematically. Number theory. Modulus arithmetic. Generalising. Creating expressions/formulae. Making and testing hypotheses. smartphone. Visualising.
Published December 2000,September 2009.
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