THIRD METHOD.
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.
FOURTH METHOD.
Desire a person to think of a number—say 6. He must then proceed as follows:
| EXAMPLE. | |
| 1. Add 1 to it | 7 |
| 2. Multiply by 3 | 21 |
| 3. Add 1 again | 22 |
| 4. Add the number thought of | 28 |
| Let him tell you the figures produced | 28 |
| 5. You then subtract 4 from it | 24 |
| 6. And divide by 4 | 6 |
Which you can say is the number he thought of.
FIFTH METHOD.
| EXAMPLE. | |
| Suppose the number thought of be | 6 |
| 1. Let him double it | 12 |
| 2. Desire him to add to this a number you tell him—say 4 | 16 |
| 3. To halve it | 8 |