We're dividing 17211117 by 399 
We're looking to find how many times 399 goes into 17211117.

Step 1:
1 divided by 399 is 0 with a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Grab the next digit (7) from the dividend, add it to 1, then carry on: 17 / 399

On to step 2:
If we divide 17 by 399, we get 0 and a remainder of 17.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 17 and we're left with 17.
Include the next digit (2) from the dividend after 17, then repeat: 172 / 399

Advancing to step 3:
399 goes into 172 0 times with a remainder of 172.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 172 and we're left with 172.
Fetch the next digit (1) from the dividend, attach it to 172 and continue: 1721 / 399

On to step 4:
The number 399 fits into 1721 4 times, leaving a remainder of 125.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
Subtracting 1596 from 1721 leaves us with 125.
Take the next digit (1) from the dividend and append it to 125, then repeat: 1251 / 399

Advancing to step 5:
The number 399 fits into 1251 3 times, leaving a remainder of 54.
Write down 3 as next digit of the result. 
Result so far: 43.0
If we take 1197 away from 1251, we end up with 54.
Include the next digit (1) from the dividend after 54, then repeat: 541 / 399

Moving on to step 6:
399 goes into 541 1 times with a remainder of 142.
Put 1 as the next digit of the answer. 
Result so far: 431.0
Subtracting 399 from 541 leaves us with 142.
Include the next digit (1) from the dividend after 142, then repeat: 1421 / 399

Advancing to step 7:
1421 divided by 399 is 3 with a remainder of 224.
The next digit of our result is 3. 
Result so far: 4313.0
Deduct 1197 from 1421 and we're left with 224.
Bring next digit (7) of the dividend behind the 224 and repeat the process: 2247 / 399

Let's proceed to step 8:
2247 divided by 399 is 5 with a remainder of 252.
Write down 5 as next digit of the result. 
Result so far: 43135.0
The remainder is 252 after subtracting 1995 from 2247.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2520, and continue the process.

Advancing to step 9:
399 goes into 2520 6 times with a remainder of 126.
The number 6 becomes the next digit in our result. 
Result so far: 43135.6
If we take 2394 away from 2520, we end up with 126.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1260, and continue the process.

Advancing to step 10:
The number 399 fits into 1260 3 times, leaving a remainder of 63.
Write down 3 as next digit of the result. 
Result so far: 43135.63
The remainder is 63 after subtracting 1197 from 1260.
Since there are no more digits in the dividend, we add a zero to the remainder making it 630, and continue the process.

Let's proceed to step 11:
399 goes into 630 1 times with a remainder of 231.
The number 1 becomes the next digit in our result. 
Result so far: 43135.631
Deduct 399 from 630 and we're left with 231.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2310, and continue the process.

Going ahead to step 12:
399 can be fit into 2310 5 times, resulting in a remainder of 315.
The next digit of our result is 5. 
Result so far: 43135.6315
If we take 1995 away from 2310, we end up with 315.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3150, and continue the process.

Moving on to step 13:
399 can be fit into 3150 7 times, resulting in a remainder of 357.
Write down 7 as next digit of the result. 
Result so far: 43135.63157
Subtracting 2793 from 3150 leaves us with 357.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3570, and continue the process.

Step 14:
When dividing 3570 by 399, we get 8 with a remainder of 378.
Write down 8 as next digit of the result. 
Result so far: 43135.631578
If we take 3192 away from 3570, we end up with 378.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3780, and continue the process.

Moving on to step 15:
If we divide 3780 by 399, we get 9 and a remainder of 189.
The next digit of our result is 9. 
Result so far: 43135.6315789
Subtracting 3591 from 3780 leaves us with 189.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1890, and continue the process.

Going ahead to step 16:
399 can be fit into 1890 4 times, resulting in a remainder of 294.
Write down 4 as next digit of the result. 
Result so far: 43135.63157894
Subtract 1596 from 1890 to get 294.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2940, and continue the process.

The final outcome is 43135.63157894, with a leftover of 2.94e-07.