Calculation:
The total numbers of integers are
⇒ 999 - 100 + 1 = 900
Let N be the number of integers with no repeated digits
Total 10 digits we have (0, 1 ........, 9)
The first digit can't be 0, we have 9 digits
For the second digit, we have 9 digits,
For the third digit, we have 8 digits
Total number of digits with no repetition
⇒ N = 9 × 9 × 8 = 648
Integers with at least one digit repeated
⇒ 900 - N
⇒ 900 - 648 = 252
∴ There will be 252 integers with at least one digit repetition.
