77580539 ÷ 399 
We want to figure out the number of times 77580539 can be divided by 399.

On to step 1:
When dividing 7 by 399, we get 0 with a remainder of 7.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Grab the next digit (7) from the dividend, add it to 7, then carry on: 77 / 399

Advancing to step 2:
If we divide 77 by 399, we get 0 and a remainder of 77.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 77 leaves us with 77.
Include the next digit (5) from the dividend after 77, then repeat: 775 / 399

Going ahead to step 3:
399 goes into 775 1 times with a remainder of 376.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we take 399 away from 775, we end up with 376.
Include the next digit (8) from the dividend after 376, then repeat: 3768 / 399

On to step 4:
When dividing 3768 by 399, we get 9 with a remainder of 177.
The next digit of our result is 9. 
Result so far: 19.0
If we take 3591 away from 3768, we end up with 177.
Fetch the next digit (0) from the dividend, attach it to 177 and continue: 1770 / 399

Advancing to step 5:
1770 divided by 399 is 4 with a remainder of 174.
Record the quotient 4 as the next digit in the result. 
Result so far: 194.0
Deduct 1596 from 1770 and we're left with 174.
Fetch the next digit (5) from the dividend, attach it to 174 and continue: 1745 / 399

Step 6:
If we divide 1745 by 399, we get 4 and a remainder of 149.
Write down 4 as next digit of the result. 
Result so far: 1944.0
Subtract 1596 from 1745 to get 149.
Grab the next digit (3) from the dividend, add it to 149, then carry on: 1493 / 399

Let's proceed to step 7:
When dividing 1493 by 399, we get 3 with a remainder of 296.
Put 3 as the next digit of the answer. 
Result so far: 19443.0
The remainder is 296 after subtracting 1197 from 1493.
Bring next digit (9) of the dividend behind the 296 and repeat the process: 2969 / 399

Moving on to step 8:
399 goes into 2969 7 times with a remainder of 176.
Record the quotient 7 as the next digit in the result. 
Result so far: 194437.0
The remainder is 176 after subtracting 2793 from 2969.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1760, and continue the process.

On to step 9:
When dividing 1760 by 399, we get 4 with a remainder of 164.
Put 4 as the next digit of the answer. 
Result so far: 194437.4
If we subtract 1596 from 1760, we get 164.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1640, and continue the process.

On to step 10:
1640 divided by 399 is 4 with a remainder of 44.
The next digit of our result is 4. 
Result so far: 194437.44
If we subtract 1596 from 1640, we get 44.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

Our division results in 194437.44 with a remaining 0.044.