81646125 ÷ 807 
The aim is to understand the frequency of 807 in 81646125.

Advancing to step 1:
If we divide 8 by 807, we get 0 and a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Grab the next digit (1) from the dividend, add it to 8, then carry on: 81 / 807

Step 2:
807 goes into 81 0 times with a remainder of 81.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 81 to get 81.
Take the next digit (6) from the dividend and append it to 81, then repeat: 816 / 807

Going ahead to step 3:
816 divided by 807 is 1 with a remainder of 9.
Write down 1 as next digit of the result. 
Result so far: 1.0
Deduct 807 from 816 and we're left with 9.
Grab the next digit (4) from the dividend, add it to 9, then carry on: 94 / 807

Let's proceed to step 4:
The number 807 fits into 94 0 times, leaving a remainder of 94.
Use 0 as the next digit of our solution. 
Result so far: 10.0
Subtract 0 from 94 to get 94.
Grab the next digit (6) from the dividend, add it to 94, then carry on: 946 / 807

Moving on to step 5:
When dividing 946 by 807, we get 1 with a remainder of 139.
Put 1 as the next digit of the answer. 
Result so far: 101.0
The remainder is 139 after subtracting 807 from 946.
Fetch the next digit (1) from the dividend, attach it to 139 and continue: 1391 / 807

Advancing to step 6:
807 goes into 1391 1 times with a remainder of 584.
Write down 1 as next digit of the result. 
Result so far: 1011.0
Subtract 807 from 1391 to get 584.
Include the next digit (2) from the dividend after 584, then repeat: 5842 / 807

Let's proceed to step 7:
807 can be fit into 5842 7 times, resulting in a remainder of 193.
The next digit of our result is 7. 
Result so far: 10117.0
If we subtract 5649 from 5842, we get 193.
Bring next digit (5) of the dividend behind the 193 and repeat the process: 1935 / 807

Moving on to step 8:
807 can be fit into 1935 2 times, resulting in a remainder of 321.
The next digit of our result is 2. 
Result so far: 101172.0
Subtract 1614 from 1935 to get 321.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3210, and continue the process.

Advancing to step 9:
When dividing 3210 by 807, we get 3 with a remainder of 789.
Write down 3 as next digit of the result. 
Result so far: 101172.3
The remainder is 789 after subtracting 2421 from 3210.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7890, and continue the process.

Advancing to step 10:
When dividing 7890 by 807, we get 9 with a remainder of 627.
Record the quotient 9 as the next digit in the result. 
Result so far: 101172.39
The remainder is 627 after subtracting 7263 from 7890.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6270, and continue the process.

Step 11:
The number 807 fits into 6270 7 times, leaving a remainder of 621.
The number 7 becomes the next digit in our result. 
Result so far: 101172.397
The remainder is 621 after subtracting 5649 from 6270.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6210, and continue the process.

On to step 12:
807 goes into 6210 7 times with a remainder of 561.
Use 7 as the next digit of our solution. 
Result so far: 101172.3977
If we take 5649 away from 6210, we end up with 561.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5610, and continue the process.

After the division, we end up with 101172.3977 and a remainder of 0.00561.