Desire a person to think of a number--say 6. He must then proceed:
EXAMPLE.
1. To multiply this number by itself 36
2. To take 1 from the number thought of 5
3. To multiply this by itself 25
4. To tell you the difference between this product
and the former 11
You must then add 1 to it 12
And halve this number 6
Which will be the number thought of.