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You have to arrange the cards in a certain order . For example,
the order for 1 2 3 4 5 would be 2 4 1 3 5
O...N...E
1...2...3
T...W...O
4...5...1
T...H...R...E...E
2...4...5...2...4
F...O...U...R
5...2...5...2...
F...I...V...E
5...5...5...5
So the cards would be arranged with
Ace in position 3
Two in position 1
Three in position 4
Four in position 2
Five in position 5
There were a number of other anonymous solutions and a solution from Andrei of School 205 Bucharest. Here is one method suggested by one person:
Let's say you have 10 cards  imagine 10 positions that represent the order of the cards in the pack
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Then you can place each card in turn in each position  using up the space so:
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
O

N

1

T

W

2

T

H

R

E

but you run out of room before you can spell out THREE so you go back to the beginning and 3 will go in position 1. The you start spelling FOUR but you have to jump over position 3 because it has a 1 in it and position 6 because it has a 2 in it, so 4 ends up in position 7:
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
3

F

1

O

U

2

4

So you end up with:
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
3

5

1

8

10

2

4

6

7

9

This method works for any number of cards and whether you use their names or their values.