77178780 ÷ 391 
We want to divide 77178780 by 391.

Let's proceed to step 1:
When dividing 7 by 391, we get 0 with a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 7 and we're left with 7.
Take the next digit (7) from the dividend and append it to 7, then repeat: 77 / 391

Going ahead to step 2:
391 can be fit into 77 0 times, resulting in a remainder of 77.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 77 leaves us with 77.
Include the next digit (1) from the dividend after 77, then repeat: 771 / 391

On to step 3:
When dividing 771 by 391, we get 1 with a remainder of 380.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Deduct 391 from 771 and we're left with 380.
Take the next digit (7) from the dividend and append it to 380, then repeat: 3807 / 391

Step 4:
391 goes into 3807 9 times with a remainder of 288.
The next digit of our result is 9. 
Result so far: 19.0
Deduct 3519 from 3807 and we're left with 288.
Include the next digit (8) from the dividend after 288, then repeat: 2888 / 391

Going ahead to step 5:
391 goes into 2888 7 times with a remainder of 151.
Record the quotient 7 as the next digit in the result. 
Result so far: 197.0
If we take 2737 away from 2888, we end up with 151.
Append the next digit (7) from the dividend to 151 and continue with: 1517 / 391

Let's proceed to step 6:
The number 391 fits into 1517 3 times, leaving a remainder of 344.
The next digit of our result is 3. 
Result so far: 1973.0
If we take 1173 away from 1517, we end up with 344.
Fetch the next digit (8) from the dividend, attach it to 344 and continue: 3448 / 391

Let's proceed to step 7:
391 can be fit into 3448 8 times, resulting in a remainder of 320.
The next digit of our result is 8. 
Result so far: 19738.0
If we subtract 3128 from 3448, we get 320.
Fetch the next digit (0) from the dividend, attach it to 320 and continue: 3200 / 391

On to step 8:
The number 391 fits into 3200 8 times, leaving a remainder of 72.
The next digit of our result is 8. 
Result so far: 197388.0
Subtracting 3128 from 3200 leaves us with 72.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

On to step 9:
720 divided by 391 is 1 with a remainder of 329.
Write down 1 as next digit of the result. 
Result so far: 197388.1
If we take 391 away from 720, we end up with 329.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3290, and continue the process.

On to step 10:
391 can be fit into 3290 8 times, resulting in a remainder of 162.
Write down 8 as next digit of the result. 
Result so far: 197388.18
The remainder is 162 after subtracting 3128 from 3290.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1620, and continue the process.

Advancing to step 11:
The number 391 fits into 1620 4 times, leaving a remainder of 56.
The number 4 becomes the next digit in our result. 
Result so far: 197388.184
Subtract 1564 from 1620 to get 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

Moving on to step 12:
560 divided by 391 is 1 with a remainder of 169.
The next digit of our result is 1. 
Result so far: 197388.1841
Deduct 391 from 560 and we're left with 169.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1690, and continue the process.

Step 13:
When dividing 1690 by 391, we get 4 with a remainder of 126.
The number 4 becomes the next digit in our result. 
Result so far: 197388.18414
If we subtract 1564 from 1690, we get 126.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1260, and continue the process.

On to step 14:
1260 divided by 391 is 3 with a remainder of 87.
Put 3 as the next digit of the answer. 
Result so far: 197388.184143
If we take 1173 away from 1260, we end up with 87.
Since there are no more digits in the dividend, we add a zero to the remainder making it 870, and continue the process.

Let's proceed to step 15:
870 divided by 391 is 2 with a remainder of 88.
Write down 2 as next digit of the result. 
Result so far: 197388.1841432
Deduct 782 from 870 and we're left with 88.
Since there are no more digits in the dividend, we add a zero to the remainder making it 880, and continue the process.

Step 16:
880 divided by 391 is 2 with a remainder of 98.
The number 2 becomes the next digit in our result. 
Result so far: 197388.18414322
If we take 782 away from 880, we end up with 98.
Since there are no more digits in the dividend, we add a zero to the remainder making it 980, and continue the process.

The final outcome is 197388.18414322, with a leftover of 9.8e-08.