How many numbers greater than 1000 can be formed using the digits 0 , 1 , 2 and 3 (repetition of digits is not allowed) ?

Step-by-step solution

To form a number greater than 1000 using the digits 0, 1, 2, 3 without repetition, the number must be a 4 -digit number. The thousands place cannot be 0 , so it can be filled in 3 ways (using 1, 2, or 3 ). The remaining 3 places can be filled with the remaining 3 digits in 3! ways. Total number of such numbers = 3 3! = 3 6 = 18 . Answer: 18