Stage: 3 Challenge Level: 
Do this as you
read...
Think of a number.
Multiply it by $3$.
Add $6$.
Take away your start number.
Divide by $2$.
Take away your number.
You have finished with $3$!
How does this work?
Number operations - generally. Creating expressions/formulae. Other equations. Algebra - generally. Number - generally. Using symbols. Integers. Generalising. Mathematical reasoning & proof. Introducing algebra.
Published February 1999.
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