We're dividing 309052 by 15 
The aim is to understand the frequency of 15 in 309052.

Step 1:
3 divided by 15 is 0 with a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Fetch the next digit (0) from the dividend, attach it to 3 and continue: 30 / 15

On to step 2:
15 goes into 30 2 times with a remainder of 0.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Deduct 30 from 30 and we're left with 0.
Include the next digit (9) from the dividend after 0, then repeat: 9 / 15

Advancing to step 3:
15 goes into 9 0 times with a remainder of 9.
The number 0 becomes the next digit in our result. 
Result so far: 20.0
The remainder is 9 after subtracting 0 from 9.
Take the next digit (0) from the dividend and append it to 9, then repeat: 90 / 15

On to step 4:
15 can be fit into 90 6 times, resulting in a remainder of 0.
The number 6 becomes the next digit in our result. 
Result so far: 206.0
The remainder is 0 after subtracting 90 from 90.
Grab the next digit (5) from the dividend, add it to 0, then carry on: 5 / 15

Moving on to step 5:
When dividing 5 by 15, we get 0 with a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 2060.0
Deduct 0 from 5 and we're left with 5.
Grab the next digit (2) from the dividend, add it to 5, then carry on: 52 / 15

Let's proceed to step 6:
52 divided by 15 is 3 with a remainder of 7.
Write down 3 as next digit of the result. 
Result so far: 20603.0
Subtracting 45 from 52 leaves us with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Going ahead to step 7:
When dividing 70 by 15, we get 4 with a remainder of 10.
The next digit of our result is 4. 
Result so far: 20603.4
If we subtract 60 from 70, 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.

Advancing to step 8:
100 divided by 15 is 6 with a remainder of 10.
Use 6 as the next digit of our solution. 
Result so far: 20603.46
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.

Step 9:
The number 15 fits into 100 6 times, leaving a remainder of 10.
The number 6 becomes the next digit in our result. 
Result so far: 20603.466
The remainder is 10 after subtracting 90 from 100.
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 20603.466, and the remainder is 0.001.