Teaching Cleveland

Lesson 6

Handout #2

TO FIND A NUMBER THOUGHT OF

First Method

  1. Let a person think of a number. (for example: 6)
  2. Let him multiply by 3. (18)
  3. Add 1. (19)
  4. Multiply by 3. (57)
  5. Add to this the number thought of. (63)
  6. Let him inform you of the number produced; it will always end with 3. Strike off the 3, and inform him that he thought of 6.

Second Method

  1. Suppose the number thought of to be (6).
  2. Let him double it. (12)
  3. Add 4. (16)
  4. Multiply by 5. (80)
  5. Add 12. (92)
  6. Multiply by 10. (920)
  7. Let him inform you of the number produced. You must then, in every case, subtract 320; the remainder is, in this example, 600; strike off the 2 ciphers (0's), and announce 6 as the number thought of.

Third Method

  1. Let a person think of a number. (for example: 6)
  2. Let him multiply this number by itself. (36)
  3. Take 1 from the number thought of. (5)
  4. Multiply this by itself. (25)
  5. Let him tell you the difference between this product and the former. (11)
  6. You must then add 1 to it. (12)
  7. And halve this number. (6)
  8. This will be the number of.


PUZZLES

To many minds, the pleasure of making a discovery, after long and patient investigation, is greater than any delight that can be offered to the senses. Puzzles may be regarded as an excellent medium for the development of such natural tendencies in youth, combining, as they do, the elements of work and play; necessitating also both application and perseverance, and enabling us to improve the valuable faculty of holding several ideas in the mind at once.

The Carpenter's Puzzle

A plank was to be cut in two; the carpenter cut it half through on each side, and found he had two feet still to cut. How was it?

The Nine Digits

Place the nine digits (that is, the several figures or numbers under ten) I three rows, in such a way that, adding them together either up or down, across, or from corner to corner, they shall always make fifteen.

The Accommodating Square

Make eight squares of paper, then divide four of them from corner to corner, so that you will now have twelve pieces. Form a square with them.

The Three Rabbits

Draw three rabbits, so that each shall appear to have two ears, while, in fact, they have only three ears between them.

Fun & Games of Long Ago. (Maynard, Massachusetts: Chandler Press 1988)

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