Software Applications Programming Errors and solutions.

Find the remainder when the digits 1 to 99 written side by side is divided by 11 i.e: (123456789101112...99)mod 11=? 123456789101112.....979899 counting from right, sum of digits at odd place = 9(9+8+...+1+0)+(9+7+5+3+1) sum of digits at even place = 10(9+8+...+1)+(8+6+4+2) sum of odd - sum of even = -40 = 4 (mod 11)