Question

How many four digit numbers are there with distinct digits ?

Answer 1

We are now left with 8 digits to fill the tens place which can be done in 8 ways. The remaining 7 digits in the units place in 7 ways. Hence by the fundamental counting principle, The number of 4-digit numbers are 9.9.8.7= 4536. Therefore, there are 4536 four-digit numbers with distinct digits.

Answer 2

Answer: Number of 4 digit numbers with distinct digits is 4536.

Step-by-step explanation:

To find : Number of 4 digit numbers with distinct digits

Solution :

For the four digit number :

At the thousand place 9 digits can be there. [Numbers from 1 to 9]

At the hundredth place 9 different digits can be present. [Numbers from 0 to 9 , except the digit at thousands place]

At the tens place 8 different digits can be present.

At the ones place 7 different digits can be present.

∴ Number of 4 digit numbers with distinct digits = 9 * 9 * 8 * 7 = 4536

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