21285 ÷ 91 
We're looking to find how many times 91 goes into 21285.

Let's proceed to step 1:
If we divide 2 by 91, we get 0 and a remainder of 2.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 2 after subtracting 0 from 2.
Take the next digit (1) from the dividend and append it to 2, then repeat: 21 / 91

On to step 2:
If we divide 21 by 91, we get 0 and a remainder of 21.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 21 after subtracting 0 from 21.
Bring next digit (2) of the dividend behind the 21 and repeat the process: 212 / 91

Step 3:
91 goes into 212 2 times with a remainder of 30.
Write down 2 as next digit of the result. 
Result so far: 2.0
Deduct 182 from 212 and we're left with 30.
Append the next digit (8) from the dividend to 30 and continue with: 308 / 91

Step 4:
If we divide 308 by 91, we get 3 and a remainder of 35.
The number 3 becomes the next digit in our result. 
Result so far: 23.0
Subtract 273 from 308 to get 35.
Grab the next digit (5) from the dividend, add it to 35, then carry on: 355 / 91

Moving on to step 5:
When dividing 355 by 91, we get 3 with a remainder of 82.
Record the quotient 3 as the next digit in the result. 
Result so far: 233.0
Subtract 273 from 355 to get 82.
Since there are no more digits in the dividend, we add a zero to the remainder making it 820, and continue the process.

Moving on to step 6:
The number 91 fits into 820 9 times, leaving a remainder of 1.
Record the quotient 9 as the next digit in the result. 
Result so far: 233.9
If we take 819 away from 820, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 7:
The number 91 fits into 10 0 times, leaving a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 233.9
The remainder is 10 after subtracting 0 from 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 8:
The number 91 fits into 100 1 times, leaving a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 233.901
The remainder is 9 after subtracting 91 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 9:
91 can be fit into 90 0 times, resulting in a remainder of 90.
The number 0 becomes the next digit in our result. 
Result so far: 233.901
Deduct 0 from 90 and we're left with 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 900, and continue the process.

On to step 10:
When dividing 900 by 91, we get 9 with a remainder of 81.
Record the quotient 9 as the next digit in the result. 
Result so far: 233.90109
The remainder is 81 after subtracting 819 from 900.
Since there are no more digits in the dividend, we add a zero to the remainder making it 810, and continue the process.

Step 11:
The number 91 fits into 810 8 times, leaving a remainder of 82.
Record the quotient 8 as the next digit in the result. 
Result so far: 233.901098
If we take 728 away from 810, we end up with 82.
Since there are no more digits in the dividend, we add a zero to the remainder making it 820, and continue the process.

On to step 12:
91 goes into 820 9 times with a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 233.9010989
The remainder is 1 after subtracting 819 from 820.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

On to step 13:
91 can be fit into 10 0 times, resulting in a remainder of 10.
The next digit of our result is 0. 
Result so far: 233.9010989
Subtracting 0 from 10 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Our division results in 233.9010989 with a remaining 1e-08.