90205520 ÷ 421 
We want to figure out the number of times 90205520 can be divided by 421.

On to step 1:
When dividing 9 by 421, we get 0 with a remainder of 9.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 9 and we're left with 9.
Include the next digit (0) from the dividend after 9, then repeat: 90 / 421

On to step 2:
When dividing 90 by 421, we get 0 with a remainder of 90.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 90 and we're left with 90.
Take the next digit (2) from the dividend and append it to 90, then repeat: 902 / 421

On to step 3:
902 divided by 421 is 2 with a remainder of 60.
Write down 2 as next digit of the result. 
Result so far: 2.0
If we subtract 842 from 902, we get 60.
Fetch the next digit (0) from the dividend, attach it to 60 and continue: 600 / 421

Step 4:
421 goes into 600 1 times with a remainder of 179.
Write down 1 as next digit of the result. 
Result so far: 21.0
If we take 421 away from 600, we end up with 179.
Include the next digit (5) from the dividend after 179, then repeat: 1795 / 421

Advancing to step 5:
421 can be fit into 1795 4 times, resulting in a remainder of 111.
Use 4 as the next digit of our solution. 
Result so far: 214.0
Subtracting 1684 from 1795 leaves us with 111.
Take the next digit (5) from the dividend and append it to 111, then repeat: 1115 / 421

Moving on to step 6:
1115 divided by 421 is 2 with a remainder of 273.
Record the quotient 2 as the next digit in the result. 
Result so far: 2142.0
The remainder is 273 after subtracting 842 from 1115.
Grab the next digit (2) from the dividend, add it to 273, then carry on: 2732 / 421

On to step 7:
421 can be fit into 2732 6 times, resulting in a remainder of 206.
Write down 6 as next digit of the result. 
Result so far: 21426.0
Subtracting 2526 from 2732 leaves us with 206.
Bring next digit (0) of the dividend behind the 206 and repeat the process: 2060 / 421

On to step 8:
If we divide 2060 by 421, we get 4 and a remainder of 376.
Use 4 as the next digit of our solution. 
Result so far: 214264.0
If we take 1684 away from 2060, we end up with 376.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3760, and continue the process.

Moving on to step 9:
If we divide 3760 by 421, we get 8 and a remainder of 392.
The number 8 becomes the next digit in our result. 
Result so far: 214264.8
Subtracting 3368 from 3760 leaves us with 392.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3920, and continue the process.

Step 10:
The number 421 fits into 3920 9 times, leaving a remainder of 131.
The next digit of our result is 9. 
Result so far: 214264.89
Subtracting 3789 from 3920 leaves us with 131.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1310, and continue the process.

Moving on to step 11:
If we divide 1310 by 421, we get 3 and a remainder of 47.
Use 3 as the next digit of our solution. 
Result so far: 214264.893
Subtracting 1263 from 1310 leaves us with 47.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

Step 12:
The number 421 fits into 470 1 times, leaving a remainder of 49.
Put 1 as the next digit of the answer. 
Result so far: 214264.8931
Subtract 421 from 470 to get 49.
Since there are no more digits in the dividend, we add a zero to the remainder making it 490, and continue the process.

Going ahead to step 13:
When dividing 490 by 421, we get 1 with a remainder of 69.
Use 1 as the next digit of our solution. 
Result so far: 214264.89311
Subtracting 421 from 490 leaves us with 69.
Since there are no more digits in the dividend, we add a zero to the remainder making it 690, and continue the process.

Our division results in 214264.89311 with a remaining 6.9e-05.