We look at the division of 86025 by 21 
Let's see how many times 21 fits into 86025.

Advancing to step 1:
When dividing 8 by 21, we get 0 with a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 8 after subtracting 0 from 8.
Fetch the next digit (6) from the dividend, attach it to 8 and continue: 86 / 21

Let's proceed to step 2:
86 divided by 21 is 4 with a remainder of 2.
Put 4 as the next digit of the answer. 
Result so far: 4.0
Subtract 84 from 86 to get 2.
Bring next digit (0) of the dividend behind the 2 and repeat the process: 20 / 21

Let's proceed to step 3:
If we divide 20 by 21, we get 0 and a remainder of 20.
The next digit of our result is 0. 
Result so far: 40.0
Subtract 0 from 20 to get 20.
Bring next digit (2) of the dividend behind the 20 and repeat the process: 202 / 21

Advancing to step 4:
If we divide 202 by 21, we get 9 and a remainder of 13.
Write down 9 as next digit of the result. 
Result so far: 409.0
If we subtract 189 from 202, we get 13.
Grab the next digit (5) from the dividend, add it to 13, then carry on: 135 / 21

Let's proceed to step 5:
21 can be fit into 135 6 times, resulting in a remainder of 9.
The next digit of our result is 6. 
Result so far: 4096.0
Subtracting 126 from 135 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.

Moving on to step 6:
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: 4096.4
If we take 84 away from 90, we end up 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.

Let's proceed to step 7:
60 divided by 21 is 2 with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 4096.42
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.

Moving on to step 8:
The number 21 fits into 180 8 times, leaving a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 4096.428
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.

Going ahead to step 9:
When dividing 120 by 21, we get 5 with a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 4096.4285
The remainder is 15 after subtracting 105 from 120.
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 10:
When dividing 150 by 21, we get 7 with a remainder of 3.
The next digit of our result is 7. 
Result so far: 4096.42857
Subtracting 147 from 150 leaves us 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.

Advancing to step 11:
When dividing 30 by 21, we get 1 with a remainder of 9.
The next digit of our result is 1. 
Result so far: 4096.428571
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.

Let's proceed to step 12:
21 can be fit into 90 4 times, resulting in a remainder of 6.
Record the quotient 4 as the next digit in the result. 
Result so far: 4096.4285714
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.

Step 13:
21 goes into 60 2 times with a remainder of 18.
The next digit of our result is 2. 
Result so far: 4096.42857142
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.

The final result is 4096.42857142 with a remainder of 1.8e-08.