843809 ÷ 15 
The aim is to understand the frequency of 15 in 843809.

On to step 1:
When dividing 8 by 15, we get 0 with a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Append the next digit (4) from the dividend to 8 and continue with: 84 / 15

Going ahead to step 2:
84 divided by 15 is 5 with a remainder of 9.
The next digit of our result is 5. 
Result so far: 5.0
The remainder is 9 after subtracting 75 from 84.
Append the next digit (3) from the dividend to 9 and continue with: 93 / 15

Step 3:
If we divide 93 by 15, we get 6 and a remainder of 3.
The next digit of our result is 6. 
Result so far: 56.0
Subtract 90 from 93 to get 3.
Grab the next digit (8) from the dividend, add it to 3, then carry on: 38 / 15

Going ahead to step 4:
When dividing 38 by 15, we get 2 with a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 562.0
Subtracting 30 from 38 leaves us with 8.
Grab the next digit (0) from the dividend, add it to 8, then carry on: 80 / 15

Going ahead to step 5:
When dividing 80 by 15, we get 5 with a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 5625.0
Deduct 75 from 80 and we're left with 5.
Include the next digit (9) from the dividend after 5, then repeat: 59 / 15

Let's proceed to step 6:
The number 15 fits into 59 3 times, leaving a remainder of 14.
The number 3 becomes the next digit in our result. 
Result so far: 56253.0
Subtract 45 from 59 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.

Let's proceed to step 7:
140 divided by 15 is 9 with a remainder of 5.
Record the quotient 9 as the next digit in the result. 
Result so far: 56253.9
Subtract 135 from 140 to 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.

Advancing to step 8:
When dividing 50 by 15, we get 3 with a remainder of 5.
The number 3 becomes the next digit in our result. 
Result so far: 56253.93
If we subtract 45 from 50, 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 9:
15 goes into 50 3 times with a remainder of 5.
Write down 3 as next digit of the result. 
Result so far: 56253.933
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.

In conclusion, the division gives 56253.933 with a balance of 0.0005.