We're dividing 394874 by 21 
We want to figure out the number of times 394874 can be divided by 21.

On to step 1:
When dividing 3 by 21, we get 0 with a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 3 after subtracting 0 from 3.
Include the next digit (9) from the dividend after 3, then repeat: 39 / 21

Going ahead to step 2:
39 divided by 21 is 1 with a remainder of 18.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we take 21 away from 39, we end up with 18.
Bring next digit (4) of the dividend behind the 18 and repeat the process: 184 / 21

Step 3:
21 goes into 184 8 times with a remainder of 16.
The number 8 becomes the next digit in our result. 
Result so far: 18.0
Deduct 168 from 184 and we're left with 16.
Append the next digit (8) from the dividend to 16 and continue with: 168 / 21

On to step 4:
21 goes into 168 8 times with a remainder of 0.
The number 8 becomes the next digit in our result. 
Result so far: 188.0
Deduct 168 from 168 and we're left with 0.
Grab the next digit (7) from the dividend, add it to 0, then carry on: 7 / 21

Let's proceed to step 5:
7 divided by 21 is 0 with a remainder of 7.
Record the quotient 0 as the next digit in the result. 
Result so far: 1880.0
If we subtract 0 from 7, we get 7.
Append the next digit (4) from the dividend to 7 and continue with: 74 / 21

Going ahead to step 6:
74 divided by 21 is 3 with a remainder of 11.
Use 3 as the next digit of our solution. 
Result so far: 18803.0
If we take 63 away from 74, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Step 7:
When dividing 110 by 21, we get 5 with a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 18803.5
Subtracting 105 from 110 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 8:
21 can be fit into 50 2 times, resulting in a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 18803.52
If we subtract 42 from 50, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Moving on to step 9:
When dividing 80 by 21, we get 3 with a remainder of 17.
Use 3 as the next digit of our solution. 
Result so far: 18803.523
Deduct 63 from 80 and we're left with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Step 10:
If we divide 170 by 21, we get 8 and a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 18803.5238
Subtract 168 from 170 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Let's proceed to step 11:
20 divided by 21 is 0 with a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 18803.5238
If we take 0 away from 20, we end up with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 12:
If we divide 200 by 21, we get 9 and a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 18803.523809
If we take 189 away from 200, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 13:
21 can be fit into 110 5 times, resulting in a remainder of 5.
Use 5 as the next digit of our solution. 
Result so far: 18803.5238095
If we take 105 away from 110, we end up with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 14:
The number 21 fits into 50 2 times, leaving a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 18803.52380952
Deduct 42 from 50 and we're left with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Our division results in 18803.52380952 with a remaining 8e-09.