We look at the division of 113989 by 90 
We want to figure out the number of times 113989 can be divided by 90.

Going ahead to step 1:
If we divide 1 by 90, we get 0 and a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 1, we get 1.
Include the next digit (1) from the dividend after 1, then repeat: 11 / 90

Moving on to step 2:
If we divide 11 by 90, we get 0 and a remainder of 11.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 11 after subtracting 0 from 11.
Append the next digit (3) from the dividend to 11 and continue with: 113 / 90

Step 3:
The number 90 fits into 113 1 times, leaving a remainder of 23.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtracting 90 from 113 leaves us with 23.
Append the next digit (9) from the dividend to 23 and continue with: 239 / 90

Let's proceed to step 4:
90 can be fit into 239 2 times, resulting in a remainder of 59.
Use 2 as the next digit of our solution. 
Result so far: 12.0
Subtract 180 from 239 to get 59.
Take the next digit (8) from the dividend and append it to 59, then repeat: 598 / 90

Step 5:
The number 90 fits into 598 6 times, leaving a remainder of 58.
Put 6 as the next digit of the answer. 
Result so far: 126.0
If we subtract 540 from 598, we get 58.
Append the next digit (9) from the dividend to 58 and continue with: 589 / 90

On to step 6:
The number 90 fits into 589 6 times, leaving a remainder of 49.
The next digit of our result is 6. 
Result so far: 1266.0
If we take 540 away from 589, we end up with 49.
Since there are no more digits in the dividend, we add a zero to the remainder making it 490, and continue the process.

Step 7:
When dividing 490 by 90, we get 5 with a remainder of 40.
The next digit of our result is 5. 
Result so far: 1266.5
Deduct 450 from 490 and we're left 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:
When dividing 400 by 90, we get 4 with a remainder of 40.
Record the quotient 4 as the next digit in the result. 
Result so far: 1266.54
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.

On to step 9:
The number 90 fits into 400 4 times, leaving a remainder of 40.
Put 4 as the next digit of the answer. 
Result so far: 1266.544
Deduct 360 from 400 and we're left 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.

After the division, we end up with 1266.544 and a remainder of 0.004.