Stage: 3 Challenge Level: 
Consider all two digit numbers ($10$, $11$, . . . ,$99$). In writing down all these numbers, which digits occur least often, and which occur most often ?
What about three digit numbers, four digit numbers and so on?
Integers. Visualising. Reading and writing numbers. Place value. smartphone. Creating expressions/formulae. Interactivities. Properties of numbers. Mathematical reasoning & proof. Generalising.
Published September 1999.
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