391670 ÷ 77 
Our goal is to divide 391670 by 77.

On to step 1:
The number 77 fits into 3 0 times, leaving a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Include the next digit (9) from the dividend after 3, then repeat: 39 / 77

Going ahead to step 2:
77 can be fit into 39 0 times, resulting in a remainder of 39.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 39, we get 39.
Include the next digit (1) from the dividend after 39, then repeat: 391 / 77

Moving on to step 3:
When dividing 391 by 77, we get 5 with a remainder of 6.
The number 5 becomes the next digit in our result. 
Result so far: 5.0
If we subtract 385 from 391, we get 6.
Append the next digit (6) from the dividend to 6 and continue with: 66 / 77

On to step 4:
66 divided by 77 is 0 with a remainder of 66.
The number 0 becomes the next digit in our result. 
Result so far: 50.0
Subtracting 0 from 66 leaves us with 66.
Fetch the next digit (7) from the dividend, attach it to 66 and continue: 667 / 77

Moving on to step 5:
77 can be fit into 667 8 times, resulting in a remainder of 51.
Use 8 as the next digit of our solution. 
Result so far: 508.0
Subtracting 616 from 667 leaves us with 51.
Fetch the next digit (0) from the dividend, attach it to 51 and continue: 510 / 77

Let's proceed to step 6:
77 goes into 510 6 times with a remainder of 48.
Use 6 as the next digit of our solution. 
Result so far: 5086.0
If we take 462 away from 510, we end up with 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

On to step 7:
77 can be fit into 480 6 times, resulting in a remainder of 18.
Put 6 as the next digit of the answer. 
Result so far: 5086.6
Subtracting 462 from 480 leaves us with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Let's proceed to step 8:
When dividing 180 by 77, we get 2 with a remainder of 26.
Write down 2 as next digit of the result. 
Result so far: 5086.62
Subtract 154 from 180 to get 26.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

Going ahead to step 9:
77 goes into 260 3 times with a remainder of 29.
Use 3 as the next digit of our solution. 
Result so far: 5086.623
Deduct 231 from 260 and we're left with 29.
Since there are no more digits in the dividend, we add a zero to the remainder making it 290, and continue the process.

Moving on to step 10:
77 can be fit into 290 3 times, resulting in a remainder of 59.
Use 3 as the next digit of our solution. 
Result so far: 5086.6233
Subtract 231 from 290 to get 59.
Since there are no more digits in the dividend, we add a zero to the remainder making it 590, and continue the process.

The final outcome is 5086.6233, with a leftover of 0.00059.