Magic (actually Algebra) Tricks

….so what is going on with all of these? Can you use Algebra to show why they work?

Regifting Robin

Regifting Robin

We could start with a little mind reading – try Regifting Robin (turn the sound on).
Can you work out what is going on?


Think of a number…
Add 3
Double
Add 4
Halve
Take away the number you first thought of

Try with several different starting numbers.


Think of a small positive number

1. Square it.
2. Add the result to your original number.
3. Divide by your original number.
4. Add 17.
5. Subtract your original number.
6. Divide by 6.

Try with several different starting numbers.


Multiply any two digit number by 11.
What do you notice?
Can you prove this result?


Solutions soon if you are puzzled.

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