We look at the division of 21214635 by 398 
We want to figure out the number of times 21214635 can be divided by 398.

Going ahead to step 1:
If we divide 2 by 398, we get 0 and a remainder of 2.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 398

On to step 2:
398 can be fit into 21 0 times, resulting in a remainder of 21.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 21, we get 21.
Bring next digit (2) of the dividend behind the 21 and repeat the process: 212 / 398

Let's proceed to step 3:
The number 398 fits into 212 0 times, leaving a remainder of 212.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 212 and we're left with 212.
Include the next digit (1) from the dividend after 212, then repeat: 2121 / 398

Moving on to step 4:
398 goes into 2121 5 times with a remainder of 131.
Record the quotient 5 as the next digit in the result. 
Result so far: 5.0
If we take 1990 away from 2121, we end up with 131.
Fetch the next digit (4) from the dividend, attach it to 131 and continue: 1314 / 398

Let's proceed to step 5:
398 can be fit into 1314 3 times, resulting in a remainder of 120.
Write down 3 as next digit of the result. 
Result so far: 53.0
Subtract 1194 from 1314 to get 120.
Fetch the next digit (6) from the dividend, attach it to 120 and continue: 1206 / 398

Advancing to step 6:
398 can be fit into 1206 3 times, resulting in a remainder of 12.
The next digit of our result is 3. 
Result so far: 533.0
Deduct 1194 from 1206 and we're left with 12.
Grab the next digit (3) from the dividend, add it to 12, then carry on: 123 / 398

Advancing to step 7:
If we divide 123 by 398, we get 0 and a remainder of 123.
The number 0 becomes the next digit in our result. 
Result so far: 5330.0
If we subtract 0 from 123, we get 123.
Grab the next digit (5) from the dividend, add it to 123, then carry on: 1235 / 398

Going ahead to step 8:
398 goes into 1235 3 times with a remainder of 41.
Put 3 as the next digit of the answer. 
Result so far: 53303.0
Deduct 1194 from 1235 and we're left with 41.
Since there are no more digits in the dividend, we add a zero to the remainder making it 410, and continue the process.

Moving on to step 9:
398 can be fit into 410 1 times, resulting in a remainder of 12.
The number 1 becomes the next digit in our result. 
Result so far: 53303.1
Subtracting 398 from 410 leaves us with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 10:
If we divide 120 by 398, we get 0 and a remainder of 120.
Write down 0 as next digit of the result. 
Result so far: 53303.1
If we take 0 away from 120, we end up with 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1200, and continue the process.

Step 11:
The number 398 fits into 1200 3 times, leaving a remainder of 6.
Use 3 as the next digit of our solution. 
Result so far: 53303.103
Deduct 1194 from 1200 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 12:
398 can be fit into 60 0 times, resulting in a remainder of 60.
Put 0 as the next digit of the answer. 
Result so far: 53303.103
Deduct 0 from 60 and we're left with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Step 13:
If we divide 600 by 398, we get 1 and a remainder of 202.
Use 1 as the next digit of our solution. 
Result so far: 53303.10301
Deduct 398 from 600 and we're left with 202.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2020, and continue the process.

On to step 14:
The number 398 fits into 2020 5 times, leaving a remainder of 30.
Record the quotient 5 as the next digit in the result. 
Result so far: 53303.103015
If we take 1990 away from 2020, we end up with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Step 15:
When dividing 300 by 398, we get 0 with a remainder of 300.
Write down 0 as next digit of the result. 
Result so far: 53303.103015
If we take 0 away from 300, we end up with 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3000, and continue the process.

Step 16:
398 can be fit into 3000 7 times, resulting in a remainder of 214.
The number 7 becomes the next digit in our result. 
Result so far: 53303.10301507
If we subtract 2786 from 3000, we get 214.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2140, and continue the process.

Our division results in 53303.10301507 with a remaining 2.14e-07.