Let's divide 66851 by 7
The aim is to understand the frequency of 7 in 66851.

Advancing to step 1:
If we divide 6 by 7, we get 0 and a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Include the next digit (6) from the dividend after 6, then repeat: 66 / 7

Moving on to step 2:
66 divided by 7 is 9 with a remainder of 3.
Record the quotient 9 as the next digit in the result. 
Result so far: 9.0
Subtract 63 from 66 to get 3.
Fetch the next digit (8) from the dividend, attach it to 3 and continue: 38 / 7

Advancing to step 3:
38 divided by 7 is 5 with a remainder of 3.
Write down 5 as next digit of the result. 
Result so far: 95.0
Subtract 35 from 38 to get 3.
Take the next digit (5) from the dividend and append it to 3, then repeat: 35 / 7

On to step 4:
When dividing 35 by 7, we get 5 with a remainder of 0.
Put 5 as the next digit of the answer. 
Result so far: 955.0
If we subtract 35 from 35, we get 0.
Append the next digit (1) from the dividend to 0 and continue with: 1 / 7

Step 5:
7 goes into 1 0 times with a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 9550.0
Deduct 0 from 1 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

On to step 6:
When dividing 10 by 7, we get 1 with a remainder of 3.
Put 1 as the next digit of the answer. 
Result so far: 9550.1
The remainder is 3 after subtracting 7 from 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Let's proceed to step 7:
7 can be fit into 30 4 times, resulting in a remainder of 2.
The next digit of our result is 4. 
Result so far: 9550.14
If we subtract 28 from 30, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 8:
7 can be fit into 20 2 times, resulting in a remainder of 6.
The next digit of our result is 2. 
Result so far: 9550.142
Subtract 14 from 20 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 9:
60 divided by 7 is 8 with a remainder of 4.
The number 8 becomes the next digit in our result. 
Result so far: 9550.1428
If we subtract 56 from 60, we get 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 10:
When dividing 40 by 7, we get 5 with a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 9550.14285
Subtracting 35 from 40 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Moving on to step 11:
The number 7 fits into 50 7 times, leaving a remainder of 1.
Put 7 as the next digit of the answer. 
Result so far: 9550.142857
If we subtract 49 from 50, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 12:
7 can be fit into 10 1 times, resulting in a remainder of 3.
The number 1 becomes the next digit in our result. 
Result so far: 9550.1428571
If we subtract 7 from 10, we get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 13:
30 divided by 7 is 4 with a remainder of 2.
Put 4 as the next digit of the answer. 
Result so far: 9550.14285714
Deduct 28 from 30 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

After the division, we end up with 9550.14285714 and a remainder of 2e-09.