155991 ÷ 8 
We want to figure out the number of times 155991 can be divided by 8.

Let's proceed to step 1:
1 divided by 8 is 0 with a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Include the next digit (5) from the dividend after 1, then repeat: 15 / 8

Step 2:
15 divided by 8 is 1 with a remainder of 7.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
The remainder is 7 after subtracting 8 from 15.
Append the next digit (5) from the dividend to 7 and continue with: 75 / 8

Going ahead to step 3:
If we divide 75 by 8, we get 9 and a remainder of 3.
Use 9 as the next digit of our solution. 
Result so far: 19.0
Subtract 72 from 75 to get 3.
Append the next digit (9) from the dividend to 3 and continue with: 39 / 8

Step 4:
8 goes into 39 4 times with a remainder of 7.
The next digit of our result is 4. 
Result so far: 194.0
Subtract 32 from 39 to get 7.
Append the next digit (9) from the dividend to 7 and continue with: 79 / 8

Let's proceed to step 5:
The number 8 fits into 79 9 times, leaving a remainder of 7.
The number 9 becomes the next digit in our result. 
Result so far: 1949.0
Deduct 72 from 79 and we're left with 7.
Append the next digit (1) from the dividend to 7 and continue with: 71 / 8

Going ahead to step 6:
The number 8 fits into 71 8 times, leaving a remainder of 7.
The number 8 becomes the next digit in our result. 
Result so far: 19498.0
Subtracting 64 from 71 leaves us 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.

On to step 7:
When dividing 70 by 8, we get 8 with a remainder of 6.
Put 8 as the next digit of the answer. 
Result so far: 19498.8
If we subtract 64 from 70, we get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Going ahead to step 8:
60 divided by 8 is 7 with a remainder of 4.
The next digit of our result is 7. 
Result so far: 19498.87
The remainder is 4 after subtracting 56 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 9:
The number 8 fits into 40 5 times, leaving a remainder of 0.
Put 5 as the next digit of the answer. 
Result so far: 19498.875
The remainder is 0 after subtracting 40 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 10:
If we divide 0 by 8, we get 0 and a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 19498.875
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 11:
0 divided by 8 is 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 19498.875
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

After the division, we end up with 19498.875 and a remainder of 0.0.