TES Resources user maths126 (aka Stephen Froggatt) has shared a manual of mathematical magic tricks to put some pizzazz into your lessons.
What is it?
A booklet of 25 magic tricks introducing mathematical conundrums that you can explain in class, plus four extra. The tricks include:
Evens and odds: 21 counters are shared between two pupils. One doubles their number of counters and adds the number the other has. After hearing their answer, you reveal that you "magically" know whether they have an even or odd number of counters.
Think of a number: pupils write down a number between 1 and 20, double it, add 14 and divide by 2, then take away the original number from the total. There is a murmur of disbelief when every pupil has the answer 7.
Fibonacci sums: ask two pupils to write down two numbers below 20, one underneath the other. Then get them to create a Fibonacci sequence using their two numbers to start. Challenge them to a race where they can use calculators and you can't. Note down the number quickly on a mini-whiteboard or paper and wait for them to finish adding up for an introduction to algebraic simplification that's full of mystery.