We're dividing 366435 by 21 
Our goal is to divide 366435 by 21.

On to step 1:
If we divide 3 by 21, we get 0 and a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Grab the next digit (6) from the dividend, add it to 3, then carry on: 36 / 21

Advancing to step 2:
36 divided by 21 is 1 with a remainder of 15.
Write down 1 as next digit of the result. 
Result so far: 1.0
If we subtract 21 from 36, we get 15.
Include the next digit (6) from the dividend after 15, then repeat: 156 / 21

Going ahead to step 3:
The number 21 fits into 156 7 times, leaving a remainder of 9.
The next digit of our result is 7. 
Result so far: 17.0
Subtract 147 from 156 to get 9.
Take the next digit (4) from the dividend and append it to 9, then repeat: 94 / 21

Going ahead to step 4:
The number 21 fits into 94 4 times, leaving a remainder of 10.
Put 4 as the next digit of the answer. 
Result so far: 174.0
The remainder is 10 after subtracting 84 from 94.
Append the next digit (3) from the dividend to 10 and continue with: 103 / 21

Going ahead to step 5:
21 can be fit into 103 4 times, resulting in a remainder of 19.
The number 4 becomes the next digit in our result. 
Result so far: 1744.0
If we subtract 84 from 103, we get 19.
Take the next digit (5) from the dividend and append it to 19, then repeat: 195 / 21

Going ahead to step 6:
When dividing 195 by 21, we get 9 with a remainder of 6.
Use 9 as the next digit of our solution. 
Result so far: 17449.0
Subtract 189 from 195 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 7:
21 goes into 60 2 times with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 17449.2
The remainder is 18 after subtracting 42 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Going ahead to step 8:
21 goes into 180 8 times with a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 17449.28
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.

Moving on to step 9:
If we divide 120 by 21, we get 5 and a remainder of 15.
Use 5 as the next digit of our solution. 
Result so far: 17449.285
If we take 105 away from 120, we end up 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.

Going ahead to step 10:
If we divide 150 by 21, we get 7 and a remainder of 3.
The next digit of our result is 7. 
Result so far: 17449.2857
Subtract 147 from 150 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Moving on to step 11:
The number 21 fits into 30 1 times, leaving a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 17449.28571
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.

Step 12:
90 divided by 21 is 4 with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 17449.285714
Subtract 84 from 90 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 13:
The number 21 fits into 60 2 times, leaving a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 17449.2857142
Subtracting 42 from 60 leaves us with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Going ahead to step 14:
When dividing 180 by 21, we get 8 with a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 17449.28571428
Subtract 168 from 180 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Our division results in 17449.28571428 with a remaining 1.2e-08.