We look at the division of 788139 by 15 
We want to figure out the number of times 788139 can be divided by 15.

Let's proceed to step 1:
When dividing 7 by 15, we get 0 with a remainder of 7.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 7 and we're left with 7.
Fetch the next digit (8) from the dividend, attach it to 7 and continue: 78 / 15

Going ahead to step 2:
15 goes into 78 5 times with a remainder of 3.
The next digit of our result is 5. 
Result so far: 5.0
Subtracting 75 from 78 leaves us with 3.
Include the next digit (8) from the dividend after 3, then repeat: 38 / 15

On to step 3:
15 can be fit into 38 2 times, resulting in a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 52.0
Subtracting 30 from 38 leaves us with 8.
Fetch the next digit (1) from the dividend, attach it to 8 and continue: 81 / 15

Moving on to step 4:
When dividing 81 by 15, we get 5 with a remainder of 6.
The number 5 becomes the next digit in our result. 
Result so far: 525.0
Deduct 75 from 81 and we're left with 6.
Bring next digit (3) of the dividend behind the 6 and repeat the process: 63 / 15

On to step 5:
When dividing 63 by 15, we get 4 with a remainder of 3.
Use 4 as the next digit of our solution. 
Result so far: 5254.0
If we subtract 60 from 63, we get 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 15

On to step 6:
The number 15 fits into 39 2 times, leaving a remainder of 9.
Put 2 as the next digit of the answer. 
Result so far: 52542.0
If we take 30 away from 39, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Going ahead to step 7:
15 can be fit into 90 6 times, resulting in a remainder of 0.
The next digit of our result is 6. 
Result so far: 52542.6
If we subtract 90 from 90, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 8:
15 goes into 0 0 times with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 52542.6
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 9:
When dividing 0 by 15, we get 0 with a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 52542.6
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

After the division, we end up with 52542.6 and a remainder of 0.0.