We look at the division of 86102791 by 7 
Our goal is to divide 86102791 by 7.

Let's proceed to step 1:
8 divided by 7 is 1 with a remainder of 1.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtract 7 from 8 to get 1.
Append the next digit (6) from the dividend to 1 and continue with: 16 / 7

Going ahead to step 2:
If we divide 16 by 7, we get 2 and a remainder of 2.
Use 2 as the next digit of our solution. 
Result so far: 12.0
If we subtract 14 from 16, we get 2.
Include the next digit (1) from the dividend after 2, then repeat: 21 / 7

Moving on to step 3:
7 can be fit into 21 3 times, resulting in a remainder of 0.
Write down 3 as next digit of the result. 
Result so far: 123.0
Deduct 21 from 21 and we're left with 0.
Bring next digit (0) of the dividend behind the 0 and repeat the process: 0 / 7

On to step 4:
If we divide 0 by 7, we get 0 and a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 1230.0
Subtracting 0 from 0 leaves us with 0.
Fetch the next digit (2) from the dividend, attach it to 0 and continue: 2 / 7

Step 5:
When dividing 2 by 7, we get 0 with a remainder of 2.
Record the quotient 0 as the next digit in the result. 
Result so far: 12300.0
If we take 0 away from 2, we end up with 2.
Append the next digit (7) from the dividend to 2 and continue with: 27 / 7

Going ahead to step 6:
27 divided by 7 is 3 with a remainder of 6.
Use 3 as the next digit of our solution. 
Result so far: 123003.0
Subtract 21 from 27 to get 6.
Fetch the next digit (9) from the dividend, attach it to 6 and continue: 69 / 7

Going ahead to step 7:
When dividing 69 by 7, we get 9 with a remainder of 6.
Use 9 as the next digit of our solution. 
Result so far: 1230039.0
If we subtract 63 from 69, we get 6.
Take the next digit (1) from the dividend and append it to 6, then repeat: 61 / 7

Going ahead to step 8:
If we divide 61 by 7, we get 8 and a remainder of 5.
Use 8 as the next digit of our solution. 
Result so far: 12300398.0
Subtracting 56 from 61 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.

Let's proceed 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: 12300398.7
Deduct 49 from 50 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.

Let's proceed to step 10:
7 goes into 10 1 times with a remainder of 3.
Use 1 as the next digit of our solution. 
Result so far: 12300398.71
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.

On to step 11:
If we divide 30 by 7, we get 4 and a remainder of 2.
Put 4 as the next digit of the answer. 
Result so far: 12300398.714
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.

Step 12:
If we divide 20 by 7, we get 2 and a remainder of 6.
Put 2 as the next digit of the answer. 
Result so far: 12300398.7142
Subtracting 14 from 20 leaves us 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 13:
7 goes into 60 8 times with a remainder of 4.
Put 8 as the next digit of the answer. 
Result so far: 12300398.71428
Subtract 56 from 60 to 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.

Step 14:
7 can be fit into 40 5 times, resulting in a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 12300398.714285
Subtract 35 from 40 to 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 15:
If we divide 50 by 7, we get 7 and a remainder of 1.
Put 7 as the next digit of the answer. 
Result so far: 12300398.7142857
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.

Let's proceed to step 16:
10 divided by 7 is 1 with a remainder of 3.
Write down 1 as next digit of the result. 
Result so far: 12300398.71428571
Deduct 7 from 10 and we're left 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.

The final result is 12300398.71428571 with a remainder of 3e-09.