77686519 ÷ 399 
We're looking to find how many times 399 goes into 77686519.

Moving on to step 1:
When dividing 7 by 399, we get 0 with a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 7, we end up with 7.
Fetch the next digit (7) from the dividend, attach it to 7 and continue: 77 / 399

Let's proceed to step 2:
The number 399 fits into 77 0 times, leaving a remainder of 77.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 77 leaves us with 77.
Fetch the next digit (6) from the dividend, attach it to 77 and continue: 776 / 399

Step 3:
When dividing 776 by 399, we get 1 with a remainder of 377.
The next digit of our result is 1. 
Result so far: 1.0
Subtract 399 from 776 to get 377.
Grab the next digit (8) from the dividend, add it to 377, then carry on: 3778 / 399

On to step 4:
The number 399 fits into 3778 9 times, leaving a remainder of 187.
The number 9 becomes the next digit in our result. 
Result so far: 19.0
If we take 3591 away from 3778, we end up with 187.
Take the next digit (6) from the dividend and append it to 187, then repeat: 1876 / 399

Moving on to step 5:
When dividing 1876 by 399, we get 4 with a remainder of 280.
Record the quotient 4 as the next digit in the result. 
Result so far: 194.0
If we subtract 1596 from 1876, we get 280.
Include the next digit (5) from the dividend after 280, then repeat: 2805 / 399

Moving on to step 6:
When dividing 2805 by 399, we get 7 with a remainder of 12.
The number 7 becomes the next digit in our result. 
Result so far: 1947.0
The remainder is 12 after subtracting 2793 from 2805.
Take the next digit (1) from the dividend and append it to 12, then repeat: 121 / 399

Moving on to step 7:
If we divide 121 by 399, we get 0 and a remainder of 121.
Write down 0 as next digit of the result. 
Result so far: 19470.0
Subtracting 0 from 121 leaves us with 121.
Fetch the next digit (9) from the dividend, attach it to 121 and continue: 1219 / 399

Moving on to step 8:
The number 399 fits into 1219 3 times, leaving a remainder of 22.
Put 3 as the next digit of the answer. 
Result so far: 194703.0
The remainder is 22 after subtracting 1197 from 1219.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

On to step 9:
If we divide 220 by 399, we get 0 and a remainder of 220.
The number 0 becomes the next digit in our result. 
Result so far: 194703.0
Subtract 0 from 220 to get 220.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2200, and continue the process.

Let's proceed to step 10:
If we divide 2200 by 399, we get 5 and a remainder of 205.
Record the quotient 5 as the next digit in the result. 
Result so far: 194703.05
If we subtract 1995 from 2200, we get 205.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2050, and continue the process.

Moving on to step 11:
399 can be fit into 2050 5 times, resulting in a remainder of 55.
The next digit of our result is 5. 
Result so far: 194703.055
If we subtract 1995 from 2050, we get 55.
Since there are no more digits in the dividend, we add a zero to the remainder making it 550, and continue the process.

The final outcome is 194703.055, with a leftover of 0.0055.