Let's divide 400386 by 21
We want to divide 400386 by 21.

Advancing to step 1:
4 divided by 21 is 0 with a remainder of 4.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 4 leaves us with 4.
Include the next digit (0) from the dividend after 4, then repeat: 40 / 21

Let's proceed to step 2:
21 goes into 40 1 times with a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we subtract 21 from 40, we get 19.
Append the next digit (0) from the dividend to 19 and continue with: 190 / 21

Going ahead to step 3:
21 goes into 190 9 times with a remainder of 1.
The next digit of our result is 9. 
Result so far: 19.0
If we take 189 away from 190, we end up with 1.
Include the next digit (3) from the dividend after 1, then repeat: 13 / 21

Let's proceed to step 4:
21 goes into 13 0 times with a remainder of 13.
The next digit of our result is 0. 
Result so far: 190.0
Subtracting 0 from 13 leaves us with 13.
Append the next digit (8) from the dividend to 13 and continue with: 138 / 21

Moving on to step 5:
The number 21 fits into 138 6 times, leaving a remainder of 12.
The number 6 becomes the next digit in our result. 
Result so far: 1906.0
If we subtract 126 from 138, we get 12.
Grab the next digit (6) from the dividend, add it to 12, then carry on: 126 / 21

Advancing to step 6:
The number 21 fits into 126 6 times, leaving a remainder of 0.
Use 6 as the next digit of our solution. 
Result so far: 19066.0
Deduct 126 from 126 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 7:
If we divide 0 by 21, we get 0 and a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 19066.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 8:
If we divide 0 by 21, we get 0 and a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 19066.0
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Our division results in 19066.0 with a remaining 0.0.