Let's divide 390129 by 78
We're looking to find how many times 78 goes into 390129.

Going ahead to step 1:
The number 78 fits into 3 0 times, leaving a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Append the next digit (9) from the dividend to 3 and continue with: 39 / 78

Advancing to step 2:
If we divide 39 by 78, we get 0 and a remainder of 39.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 39 after subtracting 0 from 39.
Fetch the next digit (0) from the dividend, attach it to 39 and continue: 390 / 78

Let's proceed to step 3:
The number 78 fits into 390 5 times, leaving a remainder of 0.
Use 5 as the next digit of our solution. 
Result so far: 5.0
Subtracting 390 from 390 leaves us with 0.
Take the next digit (1) from the dividend and append it to 0, then repeat: 1 / 78

Let's proceed to step 4:
78 goes into 1 0 times with a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 50.0
Subtract 0 from 1 to get 1.
Take the next digit (2) from the dividend and append it to 1, then repeat: 12 / 78

Going ahead to step 5:
When dividing 12 by 78, we get 0 with a remainder of 12.
Use 0 as the next digit of our solution. 
Result so far: 500.0
Subtracting 0 from 12 leaves us with 12.
Include the next digit (9) from the dividend after 12, then repeat: 129 / 78

Advancing to step 6:
When dividing 129 by 78, we get 1 with a remainder of 51.
Record the quotient 1 as the next digit in the result. 
Result so far: 5001.0
The remainder is 51 after subtracting 78 from 129.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

Going ahead to step 7:
If we divide 510 by 78, we get 6 and a remainder of 42.
The number 6 becomes the next digit in our result. 
Result so far: 5001.6
Deduct 468 from 510 and we're left with 42.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

Advancing to step 8:
When dividing 420 by 78, we get 5 with a remainder of 30.
Use 5 as the next digit of our solution. 
Result so far: 5001.65
If we take 390 away from 420, we end up with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Moving on to step 9:
If we divide 300 by 78, we get 3 and a remainder of 66.
Write down 3 as next digit of the result. 
Result so far: 5001.653
Subtracting 234 from 300 leaves us with 66.
Since there are no more digits in the dividend, we add a zero to the remainder making it 660, and continue the process.

Let's proceed to step 10:
The number 78 fits into 660 8 times, leaving a remainder of 36.
Use 8 as the next digit of our solution. 
Result so far: 5001.6538
If we take 624 away from 660, we end up with 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Moving on to step 11:
The number 78 fits into 360 4 times, leaving a remainder of 48.
The next digit of our result is 4. 
Result so far: 5001.65384
Subtract 312 from 360 to get 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

Advancing to step 12:
When dividing 480 by 78, we get 6 with a remainder of 12.
Write down 6 as next digit of the result. 
Result so far: 5001.653846
Deduct 468 from 480 and we're left with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Let's proceed to step 13:
120 divided by 78 is 1 with a remainder of 42.
The next digit of our result is 1. 
Result so far: 5001.6538461
Subtracting 78 from 120 leaves us with 42.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

On to step 14:
78 goes into 420 5 times with a remainder of 30.
Write down 5 as next digit of the result. 
Result so far: 5001.65384615
If we take 390 away from 420, we end up with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

After the division, we end up with 5001.65384615 and a remainder of 3e-08.