1   3   5   7   9  11  13  15      2   3   6   7  10  11  14  15
 17  19  21  23  25  27  29  31     18  19  22  23  26  27  30  31
 33  35  37  39  41  43  45  47     34  35  38  39  42  43  46  47
 49  51  53  55  57  59  61  63     50  51  54  55  58  59  62  63
                        
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  4   5   6   7  12  13  14  15      8   9  10  11  12  13  14  15
 20  21  22  23  28  29  30  31     24  25  26  27  28  29  30  31
 36  37  38  39  44  45  46  47     40  41  42  43  44  45  46  47
 52  53  54  55  60  61  62  63     56  57  58  59  60  61  62  63
                      
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 16  17  18  19  20  21  22  23     32  33  34  35  36  37  38  39
 24  25  26  27  28  29  30  31     40  41  42  43  44  45  46  47
 48  49  50  51  52  53  54  55     48  49  50  51  52  53  54  55
 56  57  58  59  60  61  62  63     56  57  58  59  60  61  62  63

Think of any number from 1 to 63.
Click on ALL of the boxes in the groups where your number appears.
Click the ‘CALC’ button and the result is the number you were thinking of.
Want to try another number? Just click ‘RESET’ and try again.

For example, if you were thinking of the number 43, you would click on boxes one, two, four and six. Click ‘CALC’ and the number ’43’ will appear in the output box. If you want to guess another number, click ‘RESET’ and try again.

This ‘trick’ actually is very old but it is still performed even to this day. Usually, the six groups of numbers are written down on six cards. (Magicians refer to these as the age cards, so-called because one ‘trick’ is using these to guess someone’s age, provided that the person is not over 63 years of age.)