855024 ÷ 21 
We want to figure out the number of times 855024 can be divided by 21.

Step 1:
21 can be fit into 8 0 times, resulting in a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 8, we end up with 8.
Append the next digit (5) from the dividend to 8 and continue with: 85 / 21

On to step 2:
When dividing 85 by 21, we get 4 with a remainder of 1.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
The remainder is 1 after subtracting 84 from 85.
Append the next digit (5) from the dividend to 1 and continue with: 15 / 21

Moving on to step 3:
15 divided by 21 is 0 with a remainder of 15.
Put 0 as the next digit of the answer. 
Result so far: 40.0
If we subtract 0 from 15, we get 15.
Grab the next digit (0) from the dividend, add it to 15, then carry on: 150 / 21

Step 4:
The number 21 fits into 150 7 times, leaving a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 407.0
Deduct 147 from 150 and we're left with 3.
Bring next digit (2) of the dividend behind the 3 and repeat the process: 32 / 21

On to step 5:
21 goes into 32 1 times with a remainder of 11.
Record the quotient 1 as the next digit in the result. 
Result so far: 4071.0
The remainder is 11 after subtracting 21 from 32.
Append the next digit (4) from the dividend to 11 and continue with: 114 / 21

Let's proceed to step 6:
21 goes into 114 5 times with a remainder of 9.
The next digit of our result is 5. 
Result so far: 40715.0
If we take 105 away from 114, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Moving on to step 7:
21 goes into 90 4 times with a remainder of 6.
The number 4 becomes the next digit in our result. 
Result so far: 40715.4
The remainder is 6 after subtracting 84 from 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 8:
If we divide 60 by 21, we get 2 and a remainder of 18.
Put 2 as the next digit of the answer. 
Result so far: 40715.42
Subtract 42 from 60 to get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

On to step 9:
If we divide 180 by 21, we get 8 and a remainder of 12.
Put 8 as the next digit of the answer. 
Result so far: 40715.428
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 10:
120 divided by 21 is 5 with a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 40715.4285
If we subtract 105 from 120, we get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

On to step 11:
21 goes into 150 7 times with a remainder of 3.
The next digit of our result is 7. 
Result so far: 40715.42857
Deduct 147 from 150 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 12:
The number 21 fits into 30 1 times, leaving a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 40715.428571
Subtracting 21 from 30 leaves us with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 13:
21 can be fit into 90 4 times, resulting in a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 40715.4285714
Subtracting 84 from 90 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 14:
60 divided by 21 is 2 with a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 40715.42857142
If we take 42 away from 60, we end up with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

The quotient of the division is 40715.42857142, and the remainder is 1.8e-08.