We're dividing 512625 by 21 
We want to figure out the number of times 512625 can be divided by 21.

Step 1:
When dividing 5 by 21, we get 0 with a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Bring next digit (1) of the dividend behind the 5 and repeat the process: 51 / 21

Let's proceed to step 2:
21 can be fit into 51 2 times, resulting in a remainder of 9.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Deduct 42 from 51 and we're left with 9.
Fetch the next digit (2) from the dividend, attach it to 9 and continue: 92 / 21

Going ahead to step 3:
92 divided by 21 is 4 with a remainder of 8.
Put 4 as the next digit of the answer. 
Result so far: 24.0
If we take 84 away from 92, we end up with 8.
Grab the next digit (6) from the dividend, add it to 8, then carry on: 86 / 21

On to step 4:
The number 21 fits into 86 4 times, leaving a remainder of 2.
Put 4 as the next digit of the answer. 
Result so far: 244.0
Deduct 84 from 86 and we're left with 2.
Grab the next digit (2) from the dividend, add it to 2, then carry on: 22 / 21

On to step 5:
If we divide 22 by 21, we get 1 and a remainder of 1.
Put 1 as the next digit of the answer. 
Result so far: 2441.0
Subtracting 21 from 22 leaves us with 1.
Include the next digit (5) from the dividend after 1, then repeat: 15 / 21

Step 6:
If we divide 15 by 21, we get 0 and a remainder of 15.
The next digit of our result is 0. 
Result so far: 24410.0
Subtracting 0 from 15 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 7:
21 can be fit into 150 7 times, resulting in a remainder of 3.
The number 7 becomes the next digit in our result. 
Result so far: 24410.7
If we take 147 away from 150, we end up 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.

Step 8:
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: 24410.71
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.

Going ahead to step 9:
90 divided by 21 is 4 with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 24410.714
If we subtract 84 from 90, we get 6.
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 10:
When dividing 60 by 21, we get 2 with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 24410.7142
Deduct 42 from 60 and we're left 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.

Moving on to step 11:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 24410.71428
Deduct 168 from 180 and we're left 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.

Advancing to step 12:
120 divided by 21 is 5 with a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 24410.714285
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.

Moving on to step 13:
150 divided by 21 is 7 with a remainder of 3.
The number 7 becomes the next digit in our result. 
Result so far: 24410.7142857
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 14:
When dividing 30 by 21, we get 1 with a remainder of 9.
The next digit of our result is 1. 
Result so far: 24410.71428571
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.

Our division results in 24410.71428571 with a remaining 9e-09.