We're dividing 17143344 by 399 
We want to divide 17143344 by 399.

Step 1:
1 divided by 399 is 0 with a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Bring next digit (7) of the dividend behind the 1 and repeat the process: 17 / 399

On to step 2:
399 goes into 17 0 times with a remainder of 17.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 17 after subtracting 0 from 17.
Include the next digit (1) from the dividend after 17, then repeat: 171 / 399

Step 3:
The number 399 fits into 171 0 times, leaving a remainder of 171.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 171 leaves us with 171.
Grab the next digit (4) from the dividend, add it to 171, then carry on: 1714 / 399

Let's proceed to step 4:
The number 399 fits into 1714 4 times, leaving a remainder of 118.
The next digit of our result is 4. 
Result so far: 4.0
Subtract 1596 from 1714 to get 118.
Include the next digit (3) from the dividend after 118, then repeat: 1183 / 399

Advancing to step 5:
1183 divided by 399 is 2 with a remainder of 385.
Use 2 as the next digit of our solution. 
Result so far: 42.0
Subtract 798 from 1183 to get 385.
Bring next digit (3) of the dividend behind the 385 and repeat the process: 3853 / 399

Advancing to step 6:
When dividing 3853 by 399, we get 9 with a remainder of 262.
Use 9 as the next digit of our solution. 
Result so far: 429.0
Subtracting 3591 from 3853 leaves us with 262.
Include the next digit (4) from the dividend after 262, then repeat: 2624 / 399

Advancing to step 7:
399 can be fit into 2624 6 times, resulting in a remainder of 230.
Record the quotient 6 as the next digit in the result. 
Result so far: 4296.0
The remainder is 230 after subtracting 2394 from 2624.
Bring next digit (4) of the dividend behind the 230 and repeat the process: 2304 / 399

On to step 8:
399 goes into 2304 5 times with a remainder of 309.
The number 5 becomes the next digit in our result. 
Result so far: 42965.0
The remainder is 309 after subtracting 1995 from 2304.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3090, and continue the process.

On to step 9:
When dividing 3090 by 399, we get 7 with a remainder of 297.
The next digit of our result is 7. 
Result so far: 42965.7
Subtracting 2793 from 3090 leaves us with 297.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2970, and continue the process.

Advancing to step 10:
399 can be fit into 2970 7 times, resulting in a remainder of 177.
The next digit of our result is 7. 
Result so far: 42965.77
Subtract 2793 from 2970 to get 177.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1770, and continue the process.

Our division results in 42965.77 with a remaining 0.177.