We're dividing 17210214 by 399 
Our goal is to divide 17210214 by 399.

Going ahead to 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
Deduct 0 from 1 and we're left with 1.
Append the next digit (7) from the dividend to 1 and continue with: 17 / 399

On to step 2:
399 goes into 17 0 times with a remainder of 17.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 17 to get 17.
Append the next digit (2) from the dividend to 17 and continue with: 172 / 399

Moving on to step 3:
399 goes into 172 0 times with a remainder of 172.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 172 leaves us with 172.
Grab the next digit (1) from the dividend, add it to 172, then carry on: 1721 / 399

Let's proceed to step 4:
When dividing 1721 by 399, we get 4 with a remainder of 125.
Use 4 as the next digit of our solution. 
Result so far: 4.0
If we take 1596 away from 1721, we end up with 125.
Bring next digit (0) of the dividend behind the 125 and repeat the process: 1250 / 399

Going ahead to step 5:
399 can be fit into 1250 3 times, resulting in a remainder of 53.
Record the quotient 3 as the next digit in the result. 
Result so far: 43.0
The remainder is 53 after subtracting 1197 from 1250.
Grab the next digit (2) from the dividend, add it to 53, then carry on: 532 / 399

Let's proceed to step 6:
If we divide 532 by 399, we get 1 and a remainder of 133.
Write down 1 as next digit of the result. 
Result so far: 431.0
If we subtract 399 from 532, we get 133.
Grab the next digit (1) from the dividend, add it to 133, then carry on: 1331 / 399

Step 7:
1331 divided by 399 is 3 with a remainder of 134.
Use 3 as the next digit of our solution. 
Result so far: 4313.0
Subtracting 1197 from 1331 leaves us with 134.
Include the next digit (4) from the dividend after 134, then repeat: 1344 / 399

Moving on to step 8:
The number 399 fits into 1344 3 times, leaving a remainder of 147.
Put 3 as the next digit of the answer. 
Result so far: 43133.0
If we take 1197 away from 1344, we end up with 147.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1470, and continue the process.

On to step 9:
The number 399 fits into 1470 3 times, leaving a remainder of 273.
The number 3 becomes the next digit in our result. 
Result so far: 43133.3
Deduct 1197 from 1470 and we're left with 273.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2730, and continue the process.

Going ahead to step 10:
2730 divided by 399 is 6 with a remainder of 336.
Write down 6 as next digit of the result. 
Result so far: 43133.36
The remainder is 336 after subtracting 2394 from 2730.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3360, and continue the process.

Step 11:
The number 399 fits into 3360 8 times, leaving a remainder of 168.
The number 8 becomes the next digit in our result. 
Result so far: 43133.368
Subtract 3192 from 3360 to get 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

Advancing to step 12:
The number 399 fits into 1680 4 times, leaving a remainder of 84.
Write down 4 as next digit of the result. 
Result so far: 43133.3684
Subtracting 1596 from 1680 leaves us with 84.
Since there are no more digits in the dividend, we add a zero to the remainder making it 840, and continue the process.

Advancing to step 13:
When dividing 840 by 399, we get 2 with a remainder of 42.
Put 2 as the next digit of the answer. 
Result so far: 43133.36842
If we subtract 798 from 840, we get 42.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

Moving on to step 14:
If we divide 420 by 399, we get 1 and a remainder of 21.
The next digit of our result is 1. 
Result so far: 43133.368421
Deduct 399 from 420 and we're left with 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Advancing to step 15:
If we divide 210 by 399, we get 0 and a remainder of 210.
The number 0 becomes the next digit in our result. 
Result so far: 43133.368421
Deduct 0 from 210 and we're left with 210.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2100, and continue the process.

Let's proceed to step 16:
The number 399 fits into 2100 5 times, leaving a remainder of 105.
Put 5 as the next digit of the answer. 
Result so far: 43133.36842105
If we subtract 1995 from 2100, we get 105.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1050, and continue the process.

The final outcome is 43133.36842105, with a leftover of 1.05e-07.