850217 divided by 21 
We want to figure out the number of times 850217 can be divided by 21.

Advancing to step 1:
The number 21 fits into 8 0 times, leaving a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 8, we end up with 8.
Take the next digit (5) from the dividend and append it to 8, then repeat: 85 / 21

Moving on to step 2:
85 divided by 21 is 4 with a remainder of 1.
The next digit of our result is 4. 
Result so far: 4.0
Deduct 84 from 85 and we're left with 1.
Bring next digit (0) of the dividend behind the 1 and repeat the process: 10 / 21

Moving on to step 3:
When dividing 10 by 21, we get 0 with a remainder of 10.
The next digit of our result is 0. 
Result so far: 40.0
Subtract 0 from 10 to get 10.
Include the next digit (2) from the dividend after 10, then repeat: 102 / 21

Advancing to step 4:
21 goes into 102 4 times with a remainder of 18.
Write down 4 as next digit of the result. 
Result so far: 404.0
Deduct 84 from 102 and we're left with 18.
Grab the next digit (1) from the dividend, add it to 18, then carry on: 181 / 21

Advancing to step 5:
The number 21 fits into 181 8 times, leaving a remainder of 13.
Put 8 as the next digit of the answer. 
Result so far: 4048.0
If we subtract 168 from 181, we get 13.
Fetch the next digit (7) from the dividend, attach it to 13 and continue: 137 / 21

Let's proceed to step 6:
When dividing 137 by 21, we get 6 with a remainder of 11.
Put 6 as the next digit of the answer. 
Result so far: 40486.0
If we subtract 126 from 137, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

On to step 7:
When dividing 110 by 21, we get 5 with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 40486.5
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.

Let's proceed to step 8:
If we divide 50 by 21, we get 2 and a remainder of 8.
The next digit of our result is 2. 
Result so far: 40486.52
If we subtract 42 from 50, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Advancing to step 9:
80 divided by 21 is 3 with a remainder of 17.
The next digit of our result is 3. 
Result so far: 40486.523
If we take 63 away from 80, 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 10:
When dividing 170 by 21, we get 8 with a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 40486.5238
If we take 168 away from 170, we end up with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Moving on to step 11:
20 divided by 21 is 0 with a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 40486.5238
Subtract 0 from 20 to get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

On to step 12:
When dividing 200 by 21, we get 9 with a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 40486.523809
Subtract 189 from 200 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Moving on to step 13:
21 goes into 110 5 times with a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 40486.5238095
If we take 105 away from 110, we end up 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 14:
The number 21 fits into 50 2 times, leaving a remainder of 8.
The next digit of our result is 2. 
Result so far: 40486.52380952
Subtract 42 from 50 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Our division results in 40486.52380952 with a remaining 8e-09.