We look at the division of 843406 by 21 
We want to figure out the number of times 843406 can be divided by 21.

Advancing to step 1:
When dividing 8 by 21, we get 0 with a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 8 after subtracting 0 from 8.
Take the next digit (4) from the dividend and append it to 8, then repeat: 84 / 21

Advancing to step 2:
When dividing 84 by 21, we get 4 with a remainder of 0.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
Deduct 84 from 84 and we're left with 0.
Fetch the next digit (3) from the dividend, attach it to 0 and continue: 3 / 21

On to step 3:
21 can be fit into 3 0 times, resulting in a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 40.0
Deduct 0 from 3 and we're left with 3.
Grab the next digit (4) from the dividend, add it to 3, then carry on: 34 / 21

Step 4:
34 divided by 21 is 1 with a remainder of 13.
The number 1 becomes the next digit in our result. 
Result so far: 401.0
If we take 21 away from 34, we end up with 13.
Fetch the next digit (0) from the dividend, attach it to 13 and continue: 130 / 21

Let's proceed to step 5:
130 divided by 21 is 6 with a remainder of 4.
The number 6 becomes the next digit in our result. 
Result so far: 4016.0
Deduct 126 from 130 and we're left with 4.
Include the next digit (6) from the dividend after 4, then repeat: 46 / 21

Advancing to step 6:
If we divide 46 by 21, we get 2 and a remainder of 4.
The next digit of our result is 2. 
Result so far: 40162.0
If we subtract 42 from 46, we get 4.
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 7:
21 can be fit into 40 1 times, resulting in a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 40162.1
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 8:
When dividing 190 by 21, we get 9 with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 40162.19
If we subtract 189 from 190, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Let's proceed to step 9:
21 goes into 10 0 times with a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 40162.19
If we subtract 0 from 10, we get 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 goes into 100 4 times with a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 40162.1904
Subtracting 84 from 100 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Advancing to step 11:
The number 21 fits into 160 7 times, leaving a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 40162.19047
If we subtract 147 from 160, we get 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:
21 goes into 130 6 times with a remainder of 4.
The next digit of our result is 6. 
Result so far: 40162.190476
Subtracting 126 from 130 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 13:
If we divide 40 by 21, we get 1 and a remainder of 19.
The next digit of our result is 1. 
Result so far: 40162.1904761
The remainder is 19 after subtracting 21 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Moving on to step 14:
190 divided by 21 is 9 with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 40162.19047619
If we subtract 189 from 190, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

After the division, we end up with 40162.19047619 and a remainder of 1e-09.