We look at the division of 559641 by 21 
We want to figure out the number of times 559641 can be divided by 21.

On to step 1:
5 divided by 21 is 0 with a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 5 and we're left with 5.
Take the next digit (5) from the dividend and append it to 5, then repeat: 55 / 21

Going ahead to step 2:
If we divide 55 by 21, we get 2 and a remainder of 13.
Put 2 as the next digit of the answer. 
Result so far: 2.0
Deduct 42 from 55 and we're left with 13.
Grab the next digit (9) from the dividend, add it to 13, then carry on: 139 / 21

Let's proceed to step 3:
21 can be fit into 139 6 times, resulting in a remainder of 13.
Write down 6 as next digit of the result. 
Result so far: 26.0
The remainder is 13 after subtracting 126 from 139.
Fetch the next digit (6) from the dividend, attach it to 13 and continue: 136 / 21

On to step 4:
136 divided by 21 is 6 with a remainder of 10.
The number 6 becomes the next digit in our result. 
Result so far: 266.0
Deduct 126 from 136 and we're left with 10.
Append the next digit (4) from the dividend to 10 and continue with: 104 / 21

Let's proceed to step 5:
21 can be fit into 104 4 times, resulting in a remainder of 20.
Put 4 as the next digit of the answer. 
Result so far: 2664.0
Subtracting 84 from 104 leaves us with 20.
Append the next digit (1) from the dividend to 20 and continue with: 201 / 21

Moving on to step 6:
If we divide 201 by 21, we get 9 and a remainder of 12.
Use 9 as the next digit of our solution. 
Result so far: 26649.0
If we subtract 189 from 201, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 7:
If we divide 120 by 21, we get 5 and a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 26649.5
Subtract 105 from 120 to 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.

Advancing to step 8:
150 divided by 21 is 7 with a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 26649.57
The remainder is 3 after subtracting 147 from 150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Moving on to step 9:
When dividing 30 by 21, we get 1 with a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 26649.571
If we take 21 away from 30, 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 10:
90 divided by 21 is 4 with a remainder of 6.
Record the quotient 4 as the next digit in the result. 
Result so far: 26649.5714
Deduct 84 from 90 and we're left 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.

Advancing to step 11:
When dividing 60 by 21, we get 2 with a remainder of 18.
The next digit of our result is 2. 
Result so far: 26649.57142
If we subtract 42 from 60, we 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.

Advancing to step 12:
21 can be fit into 180 8 times, resulting in a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 26649.571428
If we take 168 away from 180, we end up with 12.
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 13:
If we divide 120 by 21, we get 5 and a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 26649.5714285
Subtracting 105 from 120 leaves us with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 14:
21 goes into 150 7 times with a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 26649.57142857
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.

After the division, we end up with 26649.57142857 and a remainder of 3e-09.