[Items to be prepared]

Please print the diagram below on paper, and make seven cards. There is nothing else to prepare.

[How to play]

Two persons play the game. One person (A) thinks up some number between 1 and 127.

The other person (B) tries to guess what that number is.

(B) shows the seven cards that were prepared one by one to (A), and asks if the number (A) has selected is on the card or not.

After (B) shows all seven cards to (A), (B) identify the number.

[How to identify the number correctly]

If (B) adds on the number on the uppermost left-hand side of the cards which (A) says contain the number, (B) will arrive as the number that (A) has selected.

For example, if the number is in the cards 2,4,5, then, it becomes 2+8+16, totaling 26.

Therefore, as (B) shows the cards one by one, when (A) responds "Yes, there is," then, just add the number on the uppermost left-hand side of those cards by mental calculation to arrive at the correct number.

[Principle]

The numbers are expressed by the binary scale.

[Application]

The ternary scale.

The decimal scale.

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