We look at the division of 308109 by 21 
We want to divide 308109 by 21.

Going ahead to step 1:
When dividing 3 by 21, we get 0 with a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Bring next digit (0) of the dividend behind the 3 and repeat the process: 30 / 21

Let's proceed to step 2:
The number 21 fits into 30 1 times, leaving a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Deduct 21 from 30 and we're left with 9.
Grab the next digit (8) from the dividend, add it to 9, then carry on: 98 / 21

Moving on to step 3:
If we divide 98 by 21, we get 4 and a remainder of 14.
Write down 4 as next digit of the result. 
Result so far: 14.0
If we subtract 84 from 98, we get 14.
Fetch the next digit (1) from the dividend, attach it to 14 and continue: 141 / 21

Advancing to step 4:
The number 21 fits into 141 6 times, leaving a remainder of 15.
Write down 6 as next digit of the result. 
Result so far: 146.0
Subtracting 126 from 141 leaves us with 15.
Grab the next digit (0) from the dividend, add it to 15, then carry on: 150 / 21

Step 5:
21 goes into 150 7 times with a remainder of 3.
The next digit of our result is 7. 
Result so far: 1467.0
If we subtract 147 from 150, we get 3.
Take the next digit (9) from the dividend and append it to 3, then repeat: 39 / 21

Let's proceed to step 6:
If we divide 39 by 21, we get 1 and a remainder of 18.
Write down 1 as next digit of the result. 
Result so far: 14671.0
The remainder is 18 after subtracting 21 from 39.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 7:
If we divide 180 by 21, we get 8 and a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 14671.8
Subtracting 168 from 180 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.

On to step 8:
If we divide 120 by 21, we get 5 and a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 14671.85
Subtract 105 from 120 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 9:
When dividing 150 by 21, we get 7 with a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 14671.857
If we take 147 away from 150, we end up with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

On to step 10:
21 can be fit into 30 1 times, resulting in a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 14671.8571
Deduct 21 from 30 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 11:
90 divided by 21 is 4 with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 14671.85714
The remainder is 6 after subtracting 84 from 90.
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:
When dividing 60 by 21, we get 2 with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 14671.857142
Subtract 42 from 60 to get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 13:
180 divided by 21 is 8 with a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 14671.8571428
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Let's proceed to step 14:
The number 21 fits into 120 5 times, leaving a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 14671.85714285
Deduct 105 from 120 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Our division results in 14671.85714285 with a remaining 1.5e-08.