Question 537760
The square of the nine-digit number 111 111 111 is an n-digit number.what is the value of n ?
<pre>
Look at the pattern:

1<sup>2</sup> = 1, a 1 digit number
11<sup>2</sup> = 121, a 3 digit number
111<sup>2</sup> = 12321, a 5 digit number
1111<sup>2</sup> = 1234321, a 7 digit number
11111<sup>2</sup> = 123454321, a 9 digit number 
111111<sup>2</sup> = 12345654321, an 11 digit number 
1111111<sup>2</sup> = 1234567654321, a 13 digit number
11111111<sup>2</sup> = 123456787654321, a 15 digit number
111111111<sup>2</sup> = 12345678987654321, a 17 digit number

It's the last one in the list, so n = 17.

Edwin</pre>