We divide 663898 by 15
The aim is to understand the frequency of 15 in 663898.

Moving on to step 1:
When dividing 6 by 15, we get 0 with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Include the next digit (6) from the dividend after 6, then repeat: 66 / 15

Let's proceed to step 2:
When dividing 66 by 15, we get 4 with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 4.0
The remainder is 6 after subtracting 60 from 66.
Grab the next digit (3) from the dividend, add it to 6, then carry on: 63 / 15

Moving on to step 3:
The number 15 fits into 63 4 times, leaving a remainder of 3.
The next digit of our result is 4. 
Result so far: 44.0
If we take 60 away from 63, we end up with 3.
Include the next digit (8) from the dividend after 3, then repeat: 38 / 15

Moving on to step 4:
If we divide 38 by 15, we get 2 and a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 442.0
Deduct 30 from 38 and we're left with 8.
Take the next digit (9) from the dividend and append it to 8, then repeat: 89 / 15

Let's proceed to step 5:
The number 15 fits into 89 5 times, leaving a remainder of 14.
The number 5 becomes the next digit in our result. 
Result so far: 4425.0
If we take 75 away from 89, we end up with 14.
Bring next digit (8) of the dividend behind the 14 and repeat the process: 148 / 15

Step 6:
15 can be fit into 148 9 times, resulting in a remainder of 13.
Write down 9 as next digit of the result. 
Result so far: 44259.0
The remainder is 13 after subtracting 135 from 148.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 7:
When dividing 130 by 15, we get 8 with a remainder of 10.
The next digit of our result is 8. 
Result so far: 44259.8
Subtract 120 from 130 to 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.

Let's proceed to step 8:
If we divide 100 by 15, we get 6 and a remainder of 10.
Put 6 as the next digit of the answer. 
Result so far: 44259.86
Deduct 90 from 100 and we're left 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.

Advancing to step 9:
When dividing 100 by 15, we get 6 with a remainder of 10.
Use 6 as the next digit of our solution. 
Result so far: 44259.866
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 quotient of the division is 44259.866, and the remainder is 0.001.