86839699 divided by 870 
Our goal is to divide 86839699 by 870.

On to step 1:
When dividing 8 by 870, we get 0 with a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 8 to get 8.
Bring next digit (6) of the dividend behind the 8 and repeat the process: 86 / 870

Moving on to step 2:
86 divided by 870 is 0 with a remainder of 86.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 86 to get 86.
Append the next digit (8) from the dividend to 86 and continue with: 868 / 870

Let's proceed to step 3:
868 divided by 870 is 0 with a remainder of 868.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 868 to get 868.
Append the next digit (3) from the dividend to 868 and continue with: 8683 / 870

Advancing to step 4:
870 can be fit into 8683 9 times, resulting in a remainder of 853.
Use 9 as the next digit of our solution. 
Result so far: 9.0
Subtracting 7830 from 8683 leaves us with 853.
Append the next digit (9) from the dividend to 853 and continue with: 8539 / 870

Going ahead to step 5:
870 can be fit into 8539 9 times, resulting in a remainder of 709.
The number 9 becomes the next digit in our result. 
Result so far: 99.0
Deduct 7830 from 8539 and we're left with 709.
Take the next digit (6) from the dividend and append it to 709, then repeat: 7096 / 870

Moving on to step 6:
When dividing 7096 by 870, we get 8 with a remainder of 136.
The next digit of our result is 8. 
Result so far: 998.0
The remainder is 136 after subtracting 6960 from 7096.
Append the next digit (9) from the dividend to 136 and continue with: 1369 / 870

On to step 7:
870 goes into 1369 1 times with a remainder of 499.
Put 1 as the next digit of the answer. 
Result so far: 9981.0
Subtract 870 from 1369 to get 499.
Include the next digit (9) from the dividend after 499, then repeat: 4999 / 870

Moving on to step 8:
If we divide 4999 by 870, we get 5 and a remainder of 649.
Use 5 as the next digit of our solution. 
Result so far: 99815.0
Subtracting 4350 from 4999 leaves us with 649.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6490, and continue the process.

Step 9:
If we divide 6490 by 870, we get 7 and a remainder of 400.
The number 7 becomes the next digit in our result. 
Result so far: 99815.7
The remainder is 400 after subtracting 6090 from 6490.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

Going ahead to step 10:
When dividing 4000 by 870, we get 4 with a remainder of 520.
Write down 4 as next digit of the result. 
Result so far: 99815.74
Subtracting 3480 from 4000 leaves us with 520.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5200, and continue the process.

Step 11:
The number 870 fits into 5200 5 times, leaving a remainder of 850.
Use 5 as the next digit of our solution. 
Result so far: 99815.745
Deduct 4350 from 5200 and we're left with 850.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8500, and continue the process.

Advancing to step 12:
870 can be fit into 8500 9 times, resulting in a remainder of 670.
Write down 9 as next digit of the result. 
Result so far: 99815.7459
The remainder is 670 after subtracting 7830 from 8500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6700, and continue the process.

On to step 13:
6700 divided by 870 is 7 with a remainder of 610.
The next digit of our result is 7. 
Result so far: 99815.74597
Deduct 6090 from 6700 and we're left with 610.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6100, and continue the process.

Going ahead to step 14:
870 can be fit into 6100 7 times, resulting in a remainder of 10.
The number 7 becomes the next digit in our result. 
Result so far: 99815.745977
If we subtract 6090 from 6100, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

After the division, we end up with 99815.745977 and a remainder of 1e-06.