We look at the division of 616164 by 81 
The aim is to understand the frequency of 81 in 616164.

Advancing to step 1:
If we divide 6 by 81, we get 0 and a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Append the next digit (1) from the dividend to 6 and continue with: 61 / 81

Let's proceed to step 2:
61 divided by 81 is 0 with a remainder of 61.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 61, we get 61.
Grab the next digit (6) from the dividend, add it to 61, then carry on: 616 / 81

Going ahead to step 3:
If we divide 616 by 81, we get 7 and a remainder of 49.
The next digit of our result is 7. 
Result so far: 7.0
If we take 567 away from 616, we end up with 49.
Append the next digit (1) from the dividend to 49 and continue with: 491 / 81

On to step 4:
491 divided by 81 is 6 with a remainder of 5.
Record the quotient 6 as the next digit in the result. 
Result so far: 76.0
Subtracting 486 from 491 leaves us with 5.
Fetch the next digit (6) from the dividend, attach it to 5 and continue: 56 / 81

Let's proceed to step 5:
56 divided by 81 is 0 with a remainder of 56.
Put 0 as the next digit of the answer. 
Result so far: 760.0
If we take 0 away from 56, we end up with 56.
Bring next digit (4) of the dividend behind the 56 and repeat the process: 564 / 81

Let's proceed to step 6:
564 divided by 81 is 6 with a remainder of 78.
Write down 6 as next digit of the result. 
Result so far: 7606.0
Deduct 486 from 564 and we're left with 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Let's proceed to step 7:
When dividing 780 by 81, we get 9 with a remainder of 51.
Write down 9 as next digit of the result. 
Result so far: 7606.9
If we take 729 away from 780, we end up with 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

Let's proceed to step 8:
When dividing 510 by 81, we get 6 with a remainder of 24.
Use 6 as the next digit of our solution. 
Result so far: 7606.96
If we take 486 away from 510, we end up with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

On to step 9:
When dividing 240 by 81, we get 2 with a remainder of 78.
Use 2 as the next digit of our solution. 
Result so far: 7606.962
Subtract 162 from 240 to get 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Going ahead to step 10:
81 goes into 780 9 times with a remainder of 51.
The next digit of our result is 9. 
Result so far: 7606.9629
Deduct 729 from 780 and we're left with 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

On to step 11:
81 can be fit into 510 6 times, resulting in a remainder of 24.
Write down 6 as next digit of the result. 
Result so far: 7606.96296
Subtract 486 from 510 to get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Going ahead to step 12:
When dividing 240 by 81, we get 2 with a remainder of 78.
Write down 2 as next digit of the result. 
Result so far: 7606.962962
Deduct 162 from 240 and we're left with 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Moving on to step 13:
81 can be fit into 780 9 times, resulting in a remainder of 51.
The next digit of our result is 9. 
Result so far: 7606.9629629
If we take 729 away from 780, we end up with 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

Going ahead to step 14:
510 divided by 81 is 6 with a remainder of 24.
Write down 6 as next digit of the result. 
Result so far: 7606.96296296
If we take 486 away from 510, we end up with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

The quotient of the division is 7606.96296296, and the remainder is 2.4e-08.