Cynthia Lanius

Card No. 1
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31

Power Cards

A Mathematical Puzzle

Choose a number from 1-31. Tell me which cards below contain the number, and I can tell you the number. How do I do it?

 
Card No. 1
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
Card No. 2
2
3
6
7
10
11
14
15
18
19
22
23
26
27
30
31
Card No. 3
4
5
6
7
12
13
14
15
20
21
22
23
28
29
30
31
Card No. 4
8
9
10
11
12
13
14
15
24
25
26
27
28
29
30
31
Card No. 5
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31

Why don't you print this page and try the puzzle with your friends?

Power Cards JAVA || Print Version || The Trick Explained || Blank Cards || Application - Binary Nos.
More of Cynthia Lanius' Math Lessons
URL http://math.rice.edu/~lanius/pro/powerp.html