We're dividing 153991 by 6 
The aim is to understand the frequency of 6 in 153991.

Moving on to step 1:
The number 6 fits into 1 0 times, leaving a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Take the next digit (5) from the dividend and append it to 1, then repeat: 15 / 6

Advancing to step 2:
6 goes into 15 2 times with a remainder of 3.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
The remainder is 3 after subtracting 12 from 15.
Fetch the next digit (3) from the dividend, attach it to 3 and continue: 33 / 6

Step 3:
When dividing 33 by 6, we get 5 with a remainder of 3.
The next digit of our result is 5. 
Result so far: 25.0
Subtract 30 from 33 to get 3.
Append the next digit (9) from the dividend to 3 and continue with: 39 / 6

Let's proceed to step 4:
39 divided by 6 is 6 with a remainder of 3.
Write down 6 as next digit of the result. 
Result so far: 256.0
Subtracting 36 from 39 leaves us with 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 6

Step 5:
6 can be fit into 39 6 times, resulting in a remainder of 3.
Put 6 as the next digit of the answer. 
Result so far: 2566.0
The remainder is 3 after subtracting 36 from 39.
Include the next digit (1) from the dividend after 3, then repeat: 31 / 6

Moving on to step 6:
6 goes into 31 5 times with a remainder of 1.
Put 5 as the next digit of the answer. 
Result so far: 25665.0
Deduct 30 from 31 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 7:
10 divided by 6 is 1 with a remainder of 4.
Record the quotient 1 as the next digit in the result. 
Result so far: 25665.1
If we subtract 6 from 10, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Advancing to step 8:
The number 6 fits into 40 6 times, leaving a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 25665.16
Deduct 36 from 40 and we're left with 4.
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 6 fits into 40 6 times, leaving a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 25665.166
If we subtract 36 from 40, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

After the division, we end up with 25665.166 and a remainder of 0.0004.