Stage: 1 Challenge Level: 
On Friday at $9$ am, the magic plant was only $2$ centimetres tall.
Every twenty four hours, it doubled its height.
Multiplication & division. Introducing algebra. Working systematically. Interactivities. Trial and improvement. Addition & subtraction. Calculators. Factors and multiples. Combinations. Investigations.
Published February 1999,October 2008.
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