We're dividing 366551 by 21 
We want to divide 366551 by 21.

Advancing to step 1:
The number 21 fits into 3 0 times, leaving a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Include the next digit (6) from the dividend after 3, then repeat: 36 / 21

On to step 2:
When dividing 36 by 21, we get 1 with a remainder of 15.
Put 1 as the next digit of the answer. 
Result so far: 1.0
If we subtract 21 from 36, we get 15.
Grab the next digit (6) from the dividend, add it to 15, then carry on: 156 / 21

Step 3:
156 divided by 21 is 7 with a remainder of 9.
The number 7 becomes the next digit in our result. 
Result so far: 17.0
If we subtract 147 from 156, we get 9.
Grab the next digit (5) from the dividend, add it to 9, then carry on: 95 / 21

Going ahead to step 4:
If we divide 95 by 21, we get 4 and a remainder of 11.
Put 4 as the next digit of the answer. 
Result so far: 174.0
If we subtract 84 from 95, we get 11.
Include the next digit (5) from the dividend after 11, then repeat: 115 / 21

On to step 5:
The number 21 fits into 115 5 times, leaving a remainder of 10.
Write down 5 as next digit of the result. 
Result so far: 1745.0
Deduct 105 from 115 and we're left with 10.
Include the next digit (1) from the dividend after 10, then repeat: 101 / 21

Going ahead to step 6:
When dividing 101 by 21, we get 4 with a remainder of 17.
Use 4 as the next digit of our solution. 
Result so far: 17454.0
If we take 84 away from 101, we end up 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.

Let's proceed to step 7:
The number 21 fits into 170 8 times, leaving a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 17454.8
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.

On to step 8:
The number 21 fits into 20 0 times, leaving a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 17454.8
The remainder is 20 after subtracting 0 from 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Step 9:
The number 21 fits into 200 9 times, leaving a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 17454.809
The remainder is 11 after subtracting 189 from 200.
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 10:
If we divide 110 by 21, we get 5 and a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 17454.8095
Deduct 105 from 110 and we're left 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.

Moving on to step 11:
21 goes into 50 2 times with a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 17454.80952
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.

On to step 12:
21 goes into 80 3 times with a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 17454.809523
If we subtract 63 from 80, we get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Moving on to step 13:
If we divide 170 by 21, we get 8 and a remainder of 2.
Use 8 as the next digit of our solution. 
Result so far: 17454.8095238
If we subtract 168 from 170, we 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.

Advancing to step 14:
If we divide 20 by 21, we get 0 and a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 17454.8095238
Deduct 0 from 20 and we're left 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.

The final outcome is 17454.8095238, with a leftover of 2e-08.