343875 ÷ 15 
The aim is to understand the frequency of 15 in 343875.

On to 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 (4) from the dividend, attach it to 3 and continue: 34 / 15

Moving on to step 2:
15 goes into 34 2 times with a remainder of 4.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
If we subtract 30 from 34, we get 4.
Bring next digit (3) of the dividend behind the 4 and repeat the process: 43 / 15

Step 3:
The number 15 fits into 43 2 times, leaving a remainder of 13.
Record the quotient 2 as the next digit in the result. 
Result so far: 22.0
Deduct 30 from 43 and we're left with 13.
Append the next digit (8) from the dividend to 13 and continue with: 138 / 15

Let's proceed to step 4:
15 can be fit into 138 9 times, resulting in a remainder of 3.
Write down 9 as next digit of the result. 
Result so far: 229.0
Deduct 135 from 138 and we're left with 3.
Fetch the next digit (7) from the dividend, attach it to 3 and continue: 37 / 15

Step 5:
When dividing 37 by 15, we get 2 with a remainder of 7.
Put 2 as the next digit of the answer. 
Result so far: 2292.0
The remainder is 7 after subtracting 30 from 37.
Grab the next digit (5) from the dividend, add it to 7, then carry on: 75 / 15

Let's proceed to step 6:
15 can be fit into 75 5 times, resulting in a remainder of 0.
Use 5 as the next digit of our solution. 
Result so far: 22925.0
If we take 75 away from 75, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 7:
When dividing 0 by 15, we get 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 22925.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 8:
If we divide 0 by 15, we get 0 and a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 22925.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The quotient of the division is 22925.0, and the remainder is 0.0.