78397991 ÷ 860 
Our goal is to divide 78397991 by 860.

Let's proceed to step 1:
When dividing 7 by 860, we get 0 with a remainder of 7.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 7 and we're left with 7.
Take the next digit (8) from the dividend and append it to 7, then repeat: 78 / 860

Moving on to step 2:
If we divide 78 by 860, we get 0 and a remainder of 78.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 78, we get 78.
Append the next digit (3) from the dividend to 78 and continue with: 783 / 860

Going ahead to step 3:
If we divide 783 by 860, we get 0 and a remainder of 783.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 783 and we're left with 783.
Fetch the next digit (9) from the dividend, attach it to 783 and continue: 7839 / 860

Moving on to step 4:
7839 divided by 860 is 9 with a remainder of 99.
Record the quotient 9 as the next digit in the result. 
Result so far: 9.0
If we take 7740 away from 7839, we end up with 99.
Take the next digit (7) from the dividend and append it to 99, then repeat: 997 / 860

Let's proceed to step 5:
997 divided by 860 is 1 with a remainder of 137.
The number 1 becomes the next digit in our result. 
Result so far: 91.0
Subtracting 860 from 997 leaves us with 137.
Include the next digit (9) from the dividend after 137, then repeat: 1379 / 860

Step 6:
When dividing 1379 by 860, we get 1 with a remainder of 519.
Use 1 as the next digit of our solution. 
Result so far: 911.0
If we subtract 860 from 1379, we get 519.
Take the next digit (9) from the dividend and append it to 519, then repeat: 5199 / 860

Advancing to step 7:
The number 860 fits into 5199 6 times, leaving a remainder of 39.
The number 6 becomes the next digit in our result. 
Result so far: 9116.0
The remainder is 39 after subtracting 5160 from 5199.
Append the next digit (1) from the dividend to 39 and continue with: 391 / 860

Let's proceed to step 8:
860 can be fit into 391 0 times, resulting in a remainder of 391.
Put 0 as the next digit of the answer. 
Result so far: 91160.0
Subtract 0 from 391 to get 391.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3910, and continue the process.

Step 9:
3910 divided by 860 is 4 with a remainder of 470.
Put 4 as the next digit of the answer. 
Result so far: 91160.4
If we take 3440 away from 3910, we end up with 470.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4700, and continue the process.

Moving on to step 10:
When dividing 4700 by 860, we get 5 with a remainder of 400.
The next digit of our result is 5. 
Result so far: 91160.45
If we subtract 4300 from 4700, we get 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

Let's proceed to step 11:
4000 divided by 860 is 4 with a remainder of 560.
Use 4 as the next digit of our solution. 
Result so far: 91160.454
If we take 3440 away from 4000, we end up with 560.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5600, and continue the process.

Step 12:
860 goes into 5600 6 times with a remainder of 440.
Write down 6 as next digit of the result. 
Result so far: 91160.4546
Subtract 5160 from 5600 to get 440.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4400, and continue the process.

Step 13:
When dividing 4400 by 860, we get 5 with a remainder of 100.
The number 5 becomes the next digit in our result. 
Result so far: 91160.45465
If we subtract 4300 from 4400, we get 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1000, and continue the process.

Going ahead to step 14:
When dividing 1000 by 860, we get 1 with a remainder of 140.
Write down 1 as next digit of the result. 
Result so far: 91160.454651
Subtracting 860 from 1000 leaves us with 140.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1400, and continue the process.

Going ahead to step 15:
If we divide 1400 by 860, we get 1 and a remainder of 540.
Use 1 as the next digit of our solution. 
Result so far: 91160.4546511
Deduct 860 from 1400 and we're left with 540.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5400, and continue the process.

The final result is 91160.4546511 with a remainder of 5.4e-06.