Stage: 3 Challenge Level: 
You may find an article on Divisibility Tests helpful.
Have a go at the interactive problem Dozens first, to practise applying your understanding of the divisibility rules.
Multiplication & division. smartphone. Secondary Number Play. Working systematically. Factors and multiples. Divisibility. Creating expressions/formulae. Games. Visualising. Generalising.
Published September 2001,January 2009,September 2011.
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