We're dividing 138991 by 17 
We're looking to find how many times 17 goes into 138991.

Going ahead to step 1:
The number 17 fits into 1 0 times, leaving a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Bring next digit (3) of the dividend behind the 1 and repeat the process: 13 / 17

Going ahead to step 2:
17 can be fit into 13 0 times, resulting in a remainder of 13.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 13 to get 13.
Grab the next digit (8) from the dividend, add it to 13, then carry on: 138 / 17

On to step 3:
138 divided by 17 is 8 with a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 8.0
The remainder is 2 after subtracting 136 from 138.
Include the next digit (9) from the dividend after 2, then repeat: 29 / 17

Going ahead to step 4:
17 can be fit into 29 1 times, resulting in a remainder of 12.
The number 1 becomes the next digit in our result. 
Result so far: 81.0
If we subtract 17 from 29, we get 12.
Include the next digit (9) from the dividend after 12, then repeat: 129 / 17

Moving on to step 5:
17 goes into 129 7 times with a remainder of 10.
Write down 7 as next digit of the result. 
Result so far: 817.0
The remainder is 10 after subtracting 119 from 129.
Fetch the next digit (1) from the dividend, attach it to 10 and continue: 101 / 17

Going ahead to step 6:
When dividing 101 by 17, we get 5 with a remainder of 16.
Record the quotient 5 as the next digit in the result. 
Result so far: 8175.0
Deduct 85 from 101 and we're left with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 7:
If we divide 160 by 17, we get 9 and a remainder of 7.
The next digit of our result is 9. 
Result so far: 8175.9
If we take 153 away from 160, we end up with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Step 8:
When dividing 70 by 17, we get 4 with a remainder of 2.
Put 4 as the next digit of the answer. 
Result so far: 8175.94
Deduct 68 from 70 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 9:
If we divide 20 by 17, we get 1 and a remainder of 3.
The number 1 becomes the next digit in our result. 
Result so far: 8175.941
If we take 17 away from 20, we end up with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Advancing to step 10:
When dividing 30 by 17, we get 1 with a remainder of 13.
The number 1 becomes the next digit in our result. 
Result so far: 8175.9411
The remainder is 13 after subtracting 17 from 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

The final result is 8175.9411 with a remainder of 0.00013.