We look at the division of 766874 by 15 
The aim is to understand the frequency of 15 in 766874.

Let's proceed to step 1:
When dividing 7 by 15, we get 0 with a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 7, we end up with 7.
Include the next digit (6) from the dividend after 7, then repeat: 76 / 15

Going ahead to step 2:
When dividing 76 by 15, we get 5 with a remainder of 1.
Use 5 as the next digit of our solution. 
Result so far: 5.0
Subtracting 75 from 76 leaves us with 1.
Include the next digit (6) from the dividend after 1, then repeat: 16 / 15

Going ahead to step 3:
16 divided by 15 is 1 with a remainder of 1.
Record the quotient 1 as the next digit in the result. 
Result so far: 51.0
The remainder is 1 after subtracting 15 from 16.
Bring next digit (8) of the dividend behind the 1 and repeat the process: 18 / 15

On to step 4:
15 goes into 18 1 times with a remainder of 3.
Write down 1 as next digit of the result. 
Result so far: 511.0
Subtracting 15 from 18 leaves us with 3.
Grab the next digit (7) from the dividend, add it to 3, then carry on: 37 / 15

On to step 5:
When dividing 37 by 15, we get 2 with a remainder of 7.
The next digit of our result is 2. 
Result so far: 5112.0
If we subtract 30 from 37, we get 7.
Grab the next digit (4) from the dividend, add it to 7, then carry on: 74 / 15

Moving on to step 6:
15 goes into 74 4 times with a remainder of 14.
Use 4 as the next digit of our solution. 
Result so far: 51124.0
Subtract 60 from 74 to get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Going ahead to step 7:
If we divide 140 by 15, we get 9 and a remainder of 5.
Write down 9 as next digit of the result. 
Result so far: 51124.9
If we take 135 away from 140, we end up with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Step 8:
The number 15 fits into 50 3 times, leaving a remainder of 5.
Write down 3 as next digit of the result. 
Result so far: 51124.93
The remainder is 5 after subtracting 45 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 9:
15 goes into 50 3 times with a remainder of 5.
Write down 3 as next digit of the result. 
Result so far: 51124.933
Deduct 45 from 50 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

The quotient of the division is 51124.933, and the remainder is 0.0005.