81510 divided by 7 
The aim is to understand the frequency of 7 in 81510.

Step 1:
When dividing 8 by 7, we get 1 with a remainder of 1.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we take 7 away from 8, we end up with 1.
Take the next digit (1) from the dividend and append it to 1, then repeat: 11 / 7

Let's proceed to step 2:
7 goes into 11 1 times with a remainder of 4.
Record the quotient 1 as the next digit in the result. 
Result so far: 11.0
Deduct 7 from 11 and we're left with 4.
Bring next digit (5) of the dividend behind the 4 and repeat the process: 45 / 7

Moving on to step 3:
45 divided by 7 is 6 with a remainder of 3.
Put 6 as the next digit of the answer. 
Result so far: 116.0
The remainder is 3 after subtracting 42 from 45.
Include the next digit (1) from the dividend after 3, then repeat: 31 / 7

Going ahead to step 4:
When dividing 31 by 7, we get 4 with a remainder of 3.
Use 4 as the next digit of our solution. 
Result so far: 1164.0
Subtract 28 from 31 to get 3.
Bring next digit (0) of the dividend behind the 3 and repeat the process: 30 / 7

Moving on to step 5:
30 divided by 7 is 4 with a remainder of 2.
The number 4 becomes the next digit in our result. 
Result so far: 11644.0
The remainder is 2 after subtracting 28 from 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Moving on to step 6:
20 divided by 7 is 2 with a remainder of 6.
The next digit of our result is 2. 
Result so far: 11644.2
The remainder is 6 after subtracting 14 from 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 7:
The number 7 fits into 60 8 times, leaving a remainder of 4.
The number 8 becomes the next digit in our result. 
Result so far: 11644.28
Subtracting 56 from 60 leaves us 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.

Advancing to step 8:
The number 7 fits into 40 5 times, leaving a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 11644.285
If we subtract 35 from 40, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 9:
If we divide 50 by 7, we get 7 and a remainder of 1.
Write down 7 as next digit of the result. 
Result so far: 11644.2857
The remainder is 1 after subtracting 49 from 50.
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 10:
The number 7 fits into 10 1 times, leaving a remainder of 3.
Use 1 as the next digit of our solution. 
Result so far: 11644.28571
If we take 7 away from 10, we end up 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.

Moving on to step 11:
When dividing 30 by 7, we get 4 with a remainder of 2.
Write down 4 as next digit of the result. 
Result so far: 11644.285714
If we take 28 away from 30, we end up 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 12:
20 divided by 7 is 2 with a remainder of 6.
The number 2 becomes the next digit in our result. 
Result so far: 11644.2857142
The remainder is 6 after subtracting 14 from 20.
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 13:
60 divided by 7 is 8 with a remainder of 4.
The number 8 becomes the next digit in our result. 
Result so far: 11644.28571428
Deduct 56 from 60 and we're left 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.

Our division results in 11644.28571428 with a remaining 4e-09.