Let's divide 309910 by 90
Our goal is to divide 309910 by 90.

Going ahead to step 1:
If we divide 3 by 90, we get 0 and a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Fetch the next digit (0) from the dividend, attach it to 3 and continue: 30 / 90

Going ahead to step 2:
If we divide 30 by 90, we get 0 and a remainder of 30.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 30, we get 30.
Fetch the next digit (9) from the dividend, attach it to 30 and continue: 309 / 90

Advancing to step 3:
309 divided by 90 is 3 with a remainder of 39.
Write down 3 as next digit of the result. 
Result so far: 3.0
The remainder is 39 after subtracting 270 from 309.
Take the next digit (9) from the dividend and append it to 39, then repeat: 399 / 90

Moving on to step 4:
399 divided by 90 is 4 with a remainder of 39.
The number 4 becomes the next digit in our result. 
Result so far: 34.0
Subtract 360 from 399 to get 39.
Append the next digit (1) from the dividend to 39 and continue with: 391 / 90

Moving on to step 5:
When dividing 391 by 90, we get 4 with a remainder of 31.
Record the quotient 4 as the next digit in the result. 
Result so far: 344.0
If we take 360 away from 391, we end up with 31.
Take the next digit (0) from the dividend and append it to 31, then repeat: 310 / 90

On to step 6:
90 can be fit into 310 3 times, resulting in a remainder of 40.
Use 3 as the next digit of our solution. 
Result so far: 3443.0
If we subtract 270 from 310, we get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Step 7:
90 goes into 400 4 times with a remainder of 40.
The number 4 becomes the next digit in our result. 
Result so far: 3443.4
Subtracting 360 from 400 leaves us with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Step 8:
90 can be fit into 400 4 times, resulting in a remainder of 40.
The next digit of our result is 4. 
Result so far: 3443.44
Subtract 360 from 400 to get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

The final outcome is 3443.44, with a leftover of 0.04.