781378 ÷ 15 
We're looking to find how many times 15 goes into 781378.

Step 1:
If we divide 7 by 15, we get 0 and a remainder of 7.
Put 0 as the next digit of the answer. 
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

Advancing to step 2:
If we divide 78 by 15, we get 5 and a remainder of 3.
The next digit of our result is 5. 
Result so far: 5.0
If we subtract 75 from 78, we get 3.
Bring next digit (1) of the dividend behind the 3 and repeat the process: 31 / 15

Going ahead to step 3:
15 goes into 31 2 times with a remainder of 1.
Use 2 as the next digit of our solution. 
Result so far: 52.0
Deduct 30 from 31 and we're left with 1.
Include the next digit (3) from the dividend after 1, then repeat: 13 / 15

Moving on to step 4:
13 divided by 15 is 0 with a remainder of 13.
Record the quotient 0 as the next digit in the result. 
Result so far: 520.0
If we take 0 away from 13, we end up with 13.
Include the next digit (7) from the dividend after 13, then repeat: 137 / 15

Let's proceed to step 5:
If we divide 137 by 15, we get 9 and a remainder of 2.
Use 9 as the next digit of our solution. 
Result so far: 5209.0
The remainder is 2 after subtracting 135 from 137.
Fetch the next digit (8) from the dividend, attach it to 2 and continue: 28 / 15

On to step 6:
15 goes into 28 1 times with a remainder of 13.
Put 1 as the next digit of the answer. 
Result so far: 52091.0
The remainder is 13 after subtracting 15 from 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Let's proceed to step 7:
If we divide 130 by 15, we get 8 and a remainder of 10.
Write down 8 as next digit of the result. 
Result so far: 52091.8
If we subtract 120 from 130, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 8:
15 can be fit into 100 6 times, resulting in a remainder of 10.
Put 6 as the next digit of the answer. 
Result so far: 52091.86
Subtracting 90 from 100 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 9:
15 goes into 100 6 times with a remainder of 10.
The number 6 becomes the next digit in our result. 
Result so far: 52091.866
Subtracting 90 from 100 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

The final outcome is 52091.866, with a leftover of 0.001.