Number - Kaprekar Number
A "Kaprekar Number" has an interesting property. Think of a number k and count the number of digits n. Then square the number k. Using the square, add the right n digits to the remaining digits on the left. If k results, you have found a Kaprekar Number.
The first Kraprekar numbers are 1, 9, 45, 55, 99, 297, 703, . . .
(Ex. Let the number be 9. Then 9 x 9= 81. The original 9 is a one digit number. Add the right 1 to the remaining 8. Thus the number 9 is a Kaprekar.)