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 Move the 2 - double the number (Posted on 2002-04-19)
A certain number ends with the digit 2. Moving the 2 from the end of the number to its front doubles it. Can you find this number?

(Hint: it's quite large)

 See The Solution Submitted by levik Rating: 4.1111 (9 votes)

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 another method | Comment 4 of 10 |
This can be approached as a division problem, and thereby proceed from left to right, and it seems as easy as the multiplication approach:

```
1

2)2

```

so place a 1 to the right in the dividend:
```
1

2)21

2

01

```

requiring a zero in the quotient, and also to the right in the dividend, and brought down:
```
10

2)210

2

010

```

leading to a 5 in the quotient and dividend:
```
105

2)2105

2

010

10

05

```

until eventually a 04 (not a 05) appears at the bottom that has to be divided by 2, so a 2 can be placed at the rightmost portion and zero out the bottom subtraction.
 Posted by Charlie on 2003-06-04 04:01:16

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