We look at the division of 72432584 by 81 
The aim is to understand the frequency of 81 in 72432584.

Let's proceed to step 1:
If we divide 7 by 81, we get 0 and a remainder of 7.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Fetch the next digit (2) from the dividend, attach it to 7 and continue: 72 / 81

Moving on to step 2:
81 can be fit into 72 0 times, resulting in a remainder of 72.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 72 after subtracting 0 from 72.
Include the next digit (4) from the dividend after 72, then repeat: 724 / 81

Going ahead to step 3:
724 divided by 81 is 8 with a remainder of 76.
Use 8 as the next digit of our solution. 
Result so far: 8.0
If we take 648 away from 724, we end up with 76.
Bring next digit (3) of the dividend behind the 76 and repeat the process: 763 / 81

Advancing to step 4:
81 goes into 763 9 times with a remainder of 34.
Write down 9 as next digit of the result. 
Result so far: 89.0
Deduct 729 from 763 and we're left with 34.
Bring next digit (2) of the dividend behind the 34 and repeat the process: 342 / 81

Going ahead to step 5:
The number 81 fits into 342 4 times, leaving a remainder of 18.
Record the quotient 4 as the next digit in the result. 
Result so far: 894.0
The remainder is 18 after subtracting 324 from 342.
Include the next digit (5) from the dividend after 18, then repeat: 185 / 81

Moving on to step 6:
The number 81 fits into 185 2 times, leaving a remainder of 23.
Put 2 as the next digit of the answer. 
Result so far: 8942.0
The remainder is 23 after subtracting 162 from 185.
Grab the next digit (8) from the dividend, add it to 23, then carry on: 238 / 81

Let's proceed to step 7:
238 divided by 81 is 2 with a remainder of 76.
Write down 2 as next digit of the result. 
Result so far: 89422.0
If we take 162 away from 238, we end up with 76.
Grab the next digit (4) from the dividend, add it to 76, then carry on: 764 / 81

On to step 8:
The number 81 fits into 764 9 times, leaving a remainder of 35.
The number 9 becomes the next digit in our result. 
Result so far: 894229.0
Deduct 729 from 764 and we're left with 35.
Since there are no more digits in the dividend, we add a zero to the remainder making it 350, and continue the process.

Moving on to step 9:
81 goes into 350 4 times with a remainder of 26.
Use 4 as the next digit of our solution. 
Result so far: 894229.4
Deduct 324 from 350 and we're left with 26.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

On to step 10:
The number 81 fits into 260 3 times, leaving a remainder of 17.
Write down 3 as next digit of the result. 
Result so far: 894229.43
Subtract 243 from 260 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Going ahead to step 11:
When dividing 170 by 81, we get 2 with a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 894229.432
If we take 162 away from 170, we end up with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

On to step 12:
When dividing 80 by 81, we get 0 with a remainder of 80.
Use 0 as the next digit of our solution. 
Result so far: 894229.432
The remainder is 80 after subtracting 0 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 800, and continue the process.

Let's proceed to step 13:
When dividing 800 by 81, we get 9 with a remainder of 71.
Write down 9 as next digit of the result. 
Result so far: 894229.43209
The remainder is 71 after subtracting 729 from 800.
Since there are no more digits in the dividend, we add a zero to the remainder making it 710, and continue the process.

Step 14:
710 divided by 81 is 8 with a remainder of 62.
Put 8 as the next digit of the answer. 
Result so far: 894229.432098
If we take 648 away from 710, we end up with 62.
Since there are no more digits in the dividend, we add a zero to the remainder making it 620, and continue the process.

Advancing to step 15:
81 goes into 620 7 times with a remainder of 53.
The number 7 becomes the next digit in our result. 
Result so far: 894229.4320987
If we take 567 away from 620, we end up with 53.
Since there are no more digits in the dividend, we add a zero to the remainder making it 530, and continue the process.

Moving on to step 16:
81 goes into 530 6 times with a remainder of 44.
Record the quotient 6 as the next digit in the result. 
Result so far: 894229.43209876
Subtracting 486 from 530 leaves us with 44.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

Our division results in 894229.43209876 with a remaining 4.4e-08.