621904 divided by 81 
The aim is to understand the frequency of 81 in 621904.

Going ahead to step 1:
81 goes into 6 0 times with a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Take the next digit (2) from the dividend and append it to 6, then repeat: 62 / 81

Let's proceed to step 2:
81 can be fit into 62 0 times, resulting in a remainder of 62.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 62, we end up with 62.
Append the next digit (1) from the dividend to 62 and continue with: 621 / 81

Moving on to step 3:
When dividing 621 by 81, we get 7 with a remainder of 54.
Put 7 as the next digit of the answer. 
Result so far: 7.0
Subtracting 567 from 621 leaves us with 54.
Grab the next digit (9) from the dividend, add it to 54, then carry on: 549 / 81

Advancing to step 4:
When dividing 549 by 81, we get 6 with a remainder of 63.
Put 6 as the next digit of the answer. 
Result so far: 76.0
Subtract 486 from 549 to get 63.
Fetch the next digit (0) from the dividend, attach it to 63 and continue: 630 / 81

Advancing to step 5:
630 divided by 81 is 7 with a remainder of 63.
The number 7 becomes the next digit in our result. 
Result so far: 767.0
Deduct 567 from 630 and we're left with 63.
Include the next digit (4) from the dividend after 63, then repeat: 634 / 81

Let's proceed to step 6:
The number 81 fits into 634 7 times, leaving a remainder of 67.
Write down 7 as next digit of the result. 
Result so far: 7677.0
Deduct 567 from 634 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 7:
When dividing 670 by 81, we get 8 with a remainder of 22.
Put 8 as the next digit of the answer. 
Result so far: 7677.8
Subtract 648 from 670 to 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.

Step 8:
220 divided by 81 is 2 with a remainder of 58.
The number 2 becomes the next digit in our result. 
Result so far: 7677.82
If we take 162 away from 220, we end up 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.

On to step 9:
The number 81 fits into 580 7 times, leaving a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 7677.827
The remainder is 13 after subtracting 567 from 580.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 10:
The number 81 fits into 130 1 times, leaving a remainder of 49.
Use 1 as the next digit of our solution. 
Result so far: 7677.8271
If we subtract 81 from 130, we 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 11:
81 can be fit into 490 6 times, resulting in a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 7677.82716
If we take 486 away from 490, we end up 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.

Let's proceed to step 12:
40 divided by 81 is 0 with a remainder of 40.
The number 0 becomes the next digit in our result. 
Result so far: 7677.82716
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 13:
The number 81 fits into 400 4 times, leaving a remainder of 76.
Put 4 as the next digit of the answer. 
Result so far: 7677.8271604
Subtracting 324 from 400 leaves us with 76.
Since there are no more digits in the dividend, we add a zero to the remainder making it 760, and continue the process.

Step 14:
The number 81 fits into 760 9 times, leaving a remainder of 31.
Use 9 as the next digit of our solution. 
Result so far: 7677.82716049
If we subtract 729 from 760, we get 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

After the division, we end up with 7677.82716049 and a remainder of 3.1e-08.