Let's divide 12063515 by 21
We're looking to find how many times 21 goes into 12063515.

Advancing to step 1:
When dividing 1 by 21, we get 0 with a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Grab the next digit (2) from the dividend, add it to 1, then carry on: 12 / 21

Moving on to step 2:
When dividing 12 by 21, we get 0 with a remainder of 12.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 12 and we're left with 12.
Append the next digit (0) from the dividend to 12 and continue with: 120 / 21

On to step 3:
If we divide 120 by 21, we get 5 and a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 5.0
If we take 105 away from 120, we end up with 15.
Bring next digit (6) of the dividend behind the 15 and repeat the process: 156 / 21

Step 4:
If we divide 156 by 21, we get 7 and a remainder of 9.
The next digit of our result is 7. 
Result so far: 57.0
Subtract 147 from 156 to get 9.
Grab the next digit (3) from the dividend, add it to 9, then carry on: 93 / 21

Moving on to step 5:
The number 21 fits into 93 4 times, leaving a remainder of 9.
The number 4 becomes the next digit in our result. 
Result so far: 574.0
Subtract 84 from 93 to get 9.
Append the next digit (5) from the dividend to 9 and continue with: 95 / 21

On to step 6:
95 divided by 21 is 4 with a remainder of 11.
Use 4 as the next digit of our solution. 
Result so far: 5744.0
Subtracting 84 from 95 leaves us with 11.
Grab the next digit (1) from the dividend, add it to 11, then carry on: 111 / 21

On to step 7:
When dividing 111 by 21, we get 5 with a remainder of 6.
Write down 5 as next digit of the result. 
Result so far: 57445.0
If we take 105 away from 111, we end up with 6.
Grab the next digit (5) from the dividend, add it to 6, then carry on: 65 / 21

Let's proceed to step 8:
21 goes into 65 3 times with a remainder of 2.
Use 3 as the next digit of our solution. 
Result so far: 574453.0
Deduct 63 from 65 and we're left 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 9:
20 divided by 21 is 0 with a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 574453.0
If we take 0 away from 20, we end up 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.

On to step 10:
21 goes into 200 9 times with a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 574453.09
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.

Let's proceed to step 11:
When dividing 110 by 21, we get 5 with a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 574453.095
If we subtract 105 from 110, we get 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 12:
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: 574453.0952
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.

Step 13:
21 can be fit into 80 3 times, resulting in a remainder of 17.
Write down 3 as next digit of the result. 
Result so far: 574453.09523
The remainder is 17 after subtracting 63 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Step 14:
170 divided by 21 is 8 with a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 574453.095238
The remainder is 2 after subtracting 168 from 170.
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 15:
If we divide 20 by 21, we get 0 and a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 574453.095238
If we subtract 0 from 20, we 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.

Let's proceed to step 16:
If we divide 200 by 21, we get 9 and a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 574453.09523809
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.

Our division results in 574453.09523809 with a remaining 1.1e-08.