21090138 ÷ 495 
We want to divide 21090138 by 495.

Let's proceed to step 1:
495 can be fit into 2 0 times, resulting in a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 2 leaves us with 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 495

Let's proceed to step 2:
When dividing 21 by 495, we get 0 with a remainder of 21.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 21, we end up with 21.
Grab the next digit (0) from the dividend, add it to 21, then carry on: 210 / 495

Moving on to step 3:
210 divided by 495 is 0 with a remainder of 210.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 210, we end up with 210.
Grab the next digit (9) from the dividend, add it to 210, then carry on: 2109 / 495

Advancing to step 4:
The number 495 fits into 2109 4 times, leaving a remainder of 129.
Use 4 as the next digit of our solution. 
Result so far: 4.0
If we subtract 1980 from 2109, we get 129.
Take the next digit (0) from the dividend and append it to 129, then repeat: 1290 / 495

Step 5:
When dividing 1290 by 495, we get 2 with a remainder of 300.
The next digit of our result is 2. 
Result so far: 42.0
Subtract 990 from 1290 to get 300.
Bring next digit (1) of the dividend behind the 300 and repeat the process: 3001 / 495

Going ahead to step 6:
495 goes into 3001 6 times with a remainder of 31.
The next digit of our result is 6. 
Result so far: 426.0
If we subtract 2970 from 3001, we get 31.
Bring next digit (3) of the dividend behind the 31 and repeat the process: 313 / 495

Advancing to step 7:
The number 495 fits into 313 0 times, leaving a remainder of 313.
Put 0 as the next digit of the answer. 
Result so far: 4260.0
Subtracting 0 from 313 leaves us with 313.
Fetch the next digit (8) from the dividend, attach it to 313 and continue: 3138 / 495

Let's proceed to step 8:
3138 divided by 495 is 6 with a remainder of 168.
Use 6 as the next digit of our solution. 
Result so far: 42606.0
Deduct 2970 from 3138 and we're left with 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

On to step 9:
If we divide 1680 by 495, we get 3 and a remainder of 195.
The next digit of our result is 3. 
Result so far: 42606.3
The remainder is 195 after subtracting 1485 from 1680.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1950, and continue the process.

On to step 10:
The number 495 fits into 1950 3 times, leaving a remainder of 465.
The number 3 becomes the next digit in our result. 
Result so far: 42606.33
Deduct 1485 from 1950 and we're left with 465.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4650, and continue the process.

The final result is 42606.33 with a remainder of 0.465.