**The total number of 9 digit numbers of different digits**

To find the total number of 9-digit numbers with different digits, we need to consider a few things. Let's break down the solution step by step:

**Step 1: Determine the range of digits**
Since we are looking for 9-digit numbers, the range of digits we can use is from 1 to 9. We cannot use 0 as it would make the number an 8-digit number.

**Step 2: Calculate the total number of combinations**
To find the total number of combinations, we can use the concept of permutations. A permutation is an arrangement of objects in a specific order. In this case, we want to find the number of arrangements of 9 different digits.

The formula for finding permutations is nPr = n! / (n-r)!, where n is the total number of objects and r is the number of objects taken at a time.

In our case, we have 9 digits to arrange. Hence, n = 9.

**Step 3: Calculate the total number of 9-digit numbers**
Since we have 9 digits to arrange, we can consider each arrangement as a distinct 9-digit number. Therefore, the total number of 9-digit numbers with different digits is the same as the total number of permutations.

Using the formula mentioned in step 2, we can calculate the total number of permutations:

9P9 = 9! / (9-9)!
= 9! / 0!
= 9!

The factorial of 9 (9!) is calculated by multiplying all the integers from 1 to 9:

9! = 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1
= 362,880

Therefore, the total number of 9-digit numbers with different digits is 362,880.

Total number of digits =10


i.e. 0,1,2,3,4,5,6,7,8,9


require 9 diffrent number 


0 cant be placed in first place 


= first place can be filled in 9 ways 


and the rest 9 blank with 9 digits in 9! ways 


total ways = 9×9!