400180 divided by 21 
We want to figure out the number of times 400180 can be divided by 21.

Let's proceed to step 1:
4 divided by 21 is 0 with a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 4, we get 4.
Grab the next digit (0) from the dividend, add it to 4, then carry on: 40 / 21

Moving on to step 2:
40 divided by 21 is 1 with a remainder of 19.
The next digit of our result is 1. 
Result so far: 1.0
The remainder is 19 after subtracting 21 from 40.
Append the next digit (0) from the dividend to 19 and continue with: 190 / 21

On to step 3:
21 goes into 190 9 times with a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 19.0
Subtract 189 from 190 to get 1.
Bring next digit (1) of the dividend behind the 1 and repeat the process: 11 / 21

Advancing to step 4:
11 divided by 21 is 0 with a remainder of 11.
Put 0 as the next digit of the answer. 
Result so far: 190.0
The remainder is 11 after subtracting 0 from 11.
Fetch the next digit (8) from the dividend, attach it to 11 and continue: 118 / 21

Moving on to step 5:
21 can be fit into 118 5 times, resulting in a remainder of 13.
Put 5 as the next digit of the answer. 
Result so far: 1905.0
If we take 105 away from 118, we end up with 13.
Include the next digit (0) from the dividend after 13, then repeat: 130 / 21

Advancing to step 6:
21 can be fit into 130 6 times, resulting in a remainder of 4.
Record the quotient 6 as the next digit in the result. 
Result so far: 19056.0
The remainder is 4 after subtracting 126 from 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 7:
If we divide 40 by 21, we get 1 and a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 19056.1
Subtracting 21 from 40 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Step 8:
If we divide 190 by 21, we get 9 and a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 19056.19
If we take 189 away from 190, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 9:
When dividing 10 by 21, we get 0 with a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 19056.19
Subtracting 0 from 10 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 10:
21 can be fit into 100 4 times, resulting in a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 19056.1904
Subtract 84 from 100 to get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 11:
The number 21 fits into 160 7 times, leaving a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 19056.19047
If we take 147 away from 160, we end up with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Advancing to step 12:
130 divided by 21 is 6 with a remainder of 4.
Put 6 as the next digit of the answer. 
Result so far: 19056.190476
The remainder is 4 after subtracting 126 from 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 13:
When dividing 40 by 21, we get 1 with a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 19056.1904761
If we subtract 21 from 40, we get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Advancing to step 14:
When dividing 190 by 21, we get 9 with a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 19056.19047619
Subtracting 189 from 190 leaves us with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Our division results in 19056.19047619 with a remaining 1e-09.