We're dividing 645836 by 21 
We want to figure out the number of times 645836 can be divided by 21.

Going ahead to step 1:
6 divided by 21 is 0 with a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Include the next digit (4) from the dividend after 6, then repeat: 64 / 21

Going ahead to step 2:
When dividing 64 by 21, we get 3 with a remainder of 1.
Write down 3 as next digit of the result. 
Result so far: 3.0
The remainder is 1 after subtracting 63 from 64.
Append the next digit (5) from the dividend to 1 and continue with: 15 / 21

Moving on to step 3:
21 can be fit into 15 0 times, resulting in a remainder of 15.
Record the quotient 0 as the next digit in the result. 
Result so far: 30.0
The remainder is 15 after subtracting 0 from 15.
Take the next digit (8) from the dividend and append it to 15, then repeat: 158 / 21

On to step 4:
21 goes into 158 7 times with a remainder of 11.
Use 7 as the next digit of our solution. 
Result so far: 307.0
Deduct 147 from 158 and we're left with 11.
Grab the next digit (3) from the dividend, add it to 11, then carry on: 113 / 21

Moving on to step 5:
113 divided by 21 is 5 with a remainder of 8.
The number 5 becomes the next digit in our result. 
Result so far: 3075.0
If we take 105 away from 113, we end up with 8.
Append the next digit (6) from the dividend to 8 and continue with: 86 / 21

Let's proceed to step 6:
21 can be fit into 86 4 times, resulting in a remainder of 2.
The next digit of our result is 4. 
Result so far: 30754.0
If we take 84 away from 86, 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 7:
21 can be fit into 20 0 times, resulting in a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 30754.0
The remainder is 20 after subtracting 0 from 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 8:
200 divided by 21 is 9 with a remainder of 11.
Use 9 as the next digit of our solution. 
Result so far: 30754.09
Deduct 189 from 200 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 9:
110 divided by 21 is 5 with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 30754.095
The remainder is 5 after subtracting 105 from 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Advancing to step 10:
When dividing 50 by 21, we get 2 with a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 30754.0952
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.

Moving on to step 11:
If we divide 80 by 21, we get 3 and a remainder of 17.
Put 3 as the next digit of the answer. 
Result so far: 30754.09523
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.

Advancing to step 12:
170 divided by 21 is 8 with a remainder of 2.
The next digit of our result is 8. 
Result so far: 30754.095238
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.

Step 13:
The number 21 fits into 20 0 times, leaving a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 30754.095238
Subtracting 0 from 20 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Going ahead to step 14:
21 goes into 200 9 times with a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 30754.09523809
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.

The quotient of the division is 30754.09523809, and the remainder is 1.1e-08.