We look at the division of 818571 by 7 
The aim is to understand the frequency of 7 in 818571.

Advancing to step 1:
When dividing 8 by 7, we get 1 with a remainder of 1.
Write down 1 as next digit of the result. 
Result so far: 1.0
The remainder is 1 after subtracting 7 from 8.
Take the next digit (1) from the dividend and append it to 1, then repeat: 11 / 7

Advancing to step 2:
11 divided by 7 is 1 with a remainder of 4.
The number 1 becomes the next digit in our result. 
Result so far: 11.0
Subtracting 7 from 11 leaves us with 4.
Take the next digit (8) from the dividend and append it to 4, then repeat: 48 / 7

Advancing to step 3:
The number 7 fits into 48 6 times, leaving a remainder of 6.
Write down 6 as next digit of the result. 
Result so far: 116.0
Subtracting 42 from 48 leaves us with 6.
Take the next digit (5) from the dividend and append it to 6, then repeat: 65 / 7

Let's proceed to step 4:
When dividing 65 by 7, we get 9 with a remainder of 2.
Write down 9 as next digit of the result. 
Result so far: 1169.0
The remainder is 2 after subtracting 63 from 65.
Grab the next digit (7) from the dividend, add it to 2, then carry on: 27 / 7

On to step 5:
27 divided by 7 is 3 with a remainder of 6.
Put 3 as the next digit of the answer. 
Result so far: 11693.0
If we subtract 21 from 27, we get 6.
Include the next digit (1) from the dividend after 6, then repeat: 61 / 7

Let's proceed to step 6:
7 goes into 61 8 times with a remainder of 5.
The next digit of our result is 8. 
Result so far: 116938.0
If we take 56 away from 61, we end up 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 7:
7 goes into 50 7 times with a remainder of 1.
Write down 7 as next digit of the result. 
Result so far: 116938.7
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.

Moving on to step 8:
When dividing 10 by 7, we get 1 with a remainder of 3.
The next digit of our result is 1. 
Result so far: 116938.71
Subtract 7 from 10 to 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.

Let's proceed to step 9:
7 goes into 30 4 times with a remainder of 2.
The next digit of our result is 4. 
Result so far: 116938.714
Subtracting 28 from 30 leaves us 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.

On to step 10:
If we divide 20 by 7, we get 2 and a remainder of 6.
Write down 2 as next digit of the result. 
Result so far: 116938.7142
Deduct 14 from 20 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

On to step 11:
7 can be fit into 60 8 times, resulting in a remainder of 4.
The next digit of our result is 8. 
Result so far: 116938.71428
The remainder is 4 after subtracting 56 from 60.
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 12:
When dividing 40 by 7, we get 5 with a remainder of 5.
Use 5 as the next digit of our solution. 
Result so far: 116938.714285
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.

Step 13:
When dividing 50 by 7, we get 7 with a remainder of 1.
The number 7 becomes the next digit in our result. 
Result so far: 116938.7142857
Subtract 49 from 50 to 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.

Step 14:
When dividing 10 by 7, we get 1 with a remainder of 3.
Use 1 as the next digit of our solution. 
Result so far: 116938.71428571
Subtracting 7 from 10 leaves us with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Our division results in 116938.71428571 with a remaining 3e-09.