We look at the division of 80354 by 15 
The aim is to understand the frequency of 15 in 80354.

On to step 1:
8 divided by 15 is 0 with a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 8 to get 8.
Take the next digit (0) from the dividend and append it to 8, then repeat: 80 / 15

Step 2:
15 goes into 80 5 times with a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 5.0
The remainder is 5 after subtracting 75 from 80.
Fetch the next digit (3) from the dividend, attach it to 5 and continue: 53 / 15

Let's proceed to step 3:
If we divide 53 by 15, we get 3 and a remainder of 8.
The number 3 becomes the next digit in our result. 
Result so far: 53.0
The remainder is 8 after subtracting 45 from 53.
Bring next digit (5) of the dividend behind the 8 and repeat the process: 85 / 15

Step 4:
If we divide 85 by 15, we get 5 and a remainder of 10.
The next digit of our result is 5. 
Result so far: 535.0
If we take 75 away from 85, we end up with 10.
Grab the next digit (4) from the dividend, add it to 10, then carry on: 104 / 15

Going ahead to step 5:
104 divided by 15 is 6 with a remainder of 14.
Use 6 as the next digit of our solution. 
Result so far: 5356.0
If we take 90 away from 104, we end up with 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 6:
15 can be fit into 140 9 times, resulting in a remainder of 5.
Record the quotient 9 as the next digit in the result. 
Result so far: 5356.9
If we subtract 135 from 140, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Going ahead to step 7:
When dividing 50 by 15, we get 3 with a remainder of 5.
The next digit of our result is 3. 
Result so far: 5356.93
If we take 45 away from 50, 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.

Let's proceed to step 8:
If we divide 50 by 15, we get 3 and a remainder of 5.
Record the quotient 3 as the next digit in the result. 
Result so far: 5356.933
Subtracting 45 from 50 leaves us 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.

Our division results in 5356.933 with a remaining 0.0005.