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**kaluwa3****Member**- Registered: 2005-12-13
- Posts: 1

Hey guys, my teacher does this game where she has 6 sheets of paper (she puts them on the overhead projector) that have numbers 1-63. Some have certain numbers, some dont. All you have to do is pick a number one-63 and tell her yes or no for each sheet of paper. I get extra credit if i figure this out and I really need the credit, but I am stunned!

I found the same exact game online. This will show you what I am talking about, just in case I wasnt clear enough.

http://javascript.internet.com/games/mind-reader.html

I would really appreciate it if you guys could tell me how to do this.

She says she doesnt memorize the numbers. I know theres a little secret to it but I cant figure it out. Thanks!!

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**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

This trick works by converting each number from 1 to 63 into binary form.

1 --> 000001

2 --> 000010

3 --> 000011

4 --> 000100

...

62 --> 111110

63 --> 111111

Each card corresponds to one digit in the binary code.

The first card contains all the numbers that have the last digit of the binary as 1.

The second card contains all the numbers that have the second-last digit as 1.

This continues until we reach the 6th card, which has all the numbers that have the first digit in the binary code as 1.

Each card has a number in the top-left (assuming your link is exactly the same as your teacher's trick). The first is 1, then 2, then 4, 8, 16 and 32.

For each card that you say yes to, your teacher adds up the top-left number on each of these and the total will be your number.

Why did the vector cross the road?

It wanted to be normal.

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,663

Work anything like This Mind Reader ?

He he.

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**justlookingforthemoment****Moderator**- Registered: 2005-05-26
- Posts: 2,161

Hey! Haven't I seen that before somewhere? Good job, Rod!

Did you look at any of the other games?

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,663

Any you like?

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