We're dividing 172156 by 81 
The aim is to understand the frequency of 81 in 172156.

Step 1:
The number 81 fits into 1 0 times, leaving a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Bring next digit (7) of the dividend behind the 1 and repeat the process: 17 / 81

Moving on to step 2:
81 goes into 17 0 times with a remainder of 17.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 17, we get 17.
Append the next digit (2) from the dividend to 17 and continue with: 172 / 81

Let's proceed to step 3:
If we divide 172 by 81, we get 2 and a remainder of 10.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
The remainder is 10 after subtracting 162 from 172.
Grab the next digit (1) from the dividend, add it to 10, then carry on: 101 / 81

On to step 4:
When dividing 101 by 81, we get 1 with a remainder of 20.
Write down 1 as next digit of the result. 
Result so far: 21.0
If we subtract 81 from 101, we get 20.
Bring next digit (5) of the dividend behind the 20 and repeat the process: 205 / 81

On to step 5:
81 can be fit into 205 2 times, resulting in a remainder of 43.
Record the quotient 2 as the next digit in the result. 
Result so far: 212.0
Subtract 162 from 205 to get 43.
Take the next digit (6) from the dividend and append it to 43, then repeat: 436 / 81

Going ahead to step 6:
436 divided by 81 is 5 with a remainder of 31.
Put 5 as the next digit of the answer. 
Result so far: 2125.0
Deduct 405 from 436 and we're left with 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

Step 7:
81 can be fit into 310 3 times, resulting in a remainder of 67.
Use 3 as the next digit of our solution. 
Result so far: 2125.3
Deduct 243 from 310 and we're left with 67.
Since there are no more digits in the dividend, we add a zero to the remainder making it 670, and continue the process.

Advancing to step 8:
670 divided by 81 is 8 with a remainder of 22.
Put 8 as the next digit of the answer. 
Result so far: 2125.38
If we subtract 648 from 670, we get 22.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Going ahead to step 9:
The number 81 fits into 220 2 times, leaving a remainder of 58.
Record the quotient 2 as the next digit in the result. 
Result so far: 2125.382
Deduct 162 from 220 and we're left with 58.
Since there are no more digits in the dividend, we add a zero to the remainder making it 580, and continue the process.

Moving on to step 10:
If we divide 580 by 81, we get 7 and a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 2125.3827
If we subtract 567 from 580, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Step 11:
130 divided by 81 is 1 with a remainder of 49.
Write down 1 as next digit of the result. 
Result so far: 2125.38271
Subtract 81 from 130 to get 49.
Since there are no more digits in the dividend, we add a zero to the remainder making it 490, and continue the process.

On to step 12:
81 goes into 490 6 times with a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 2125.382716
Deduct 486 from 490 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 13:
81 can be fit into 40 0 times, resulting in a remainder of 40.
Record the quotient 0 as the next digit in the result. 
Result so far: 2125.382716
If we subtract 0 from 40, 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.

On to step 14:
If we divide 400 by 81, we get 4 and a remainder of 76.
Put 4 as the next digit of the answer. 
Result so far: 2125.38271604
Subtract 324 from 400 to get 76.
Since there are no more digits in the dividend, we add a zero to the remainder making it 760, and continue the process.

After the division, we end up with 2125.38271604 and a remainder of 7.6e-08.