Let's divide 643211 by 15
The aim is to understand the frequency of 15 in 643211.

Advancing to step 1:
When dividing 6 by 15, we get 0 with a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 6 leaves us with 6.
Take the next digit (4) from the dividend and append it to 6, then repeat: 64 / 15

Step 2:
15 can be fit into 64 4 times, resulting in a remainder of 4.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
Subtracting 60 from 64 leaves us with 4.
Fetch the next digit (3) from the dividend, attach it to 4 and continue: 43 / 15

Step 3:
43 divided by 15 is 2 with a remainder of 13.
Record the quotient 2 as the next digit in the result. 
Result so far: 42.0
Deduct 30 from 43 and we're left with 13.
Bring next digit (2) of the dividend behind the 13 and repeat the process: 132 / 15

Moving on to step 4:
The number 15 fits into 132 8 times, leaving a remainder of 12.
Put 8 as the next digit of the answer. 
Result so far: 428.0
If we take 120 away from 132, we end up with 12.
Grab the next digit (1) from the dividend, add it to 12, then carry on: 121 / 15

Let's proceed to step 5:
121 divided by 15 is 8 with a remainder of 1.
The number 8 becomes the next digit in our result. 
Result so far: 4288.0
If we subtract 120 from 121, we get 1.
Append the next digit (1) from the dividend to 1 and continue with: 11 / 15

Let's proceed to step 6:
11 divided by 15 is 0 with a remainder of 11.
Use 0 as the next digit of our solution. 
Result so far: 42880.0
If we subtract 0 from 11, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 7:
If we divide 110 by 15, we get 7 and a remainder of 5.
Write down 7 as next digit of the result. 
Result so far: 42880.7
Subtract 105 from 110 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.

Moving on to step 8:
If we divide 50 by 15, we get 3 and a remainder of 5.
Use 3 as the next digit of our solution. 
Result so far: 42880.73
Subtract 45 from 50 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.

Let's proceed to step 9:
15 can be fit into 50 3 times, resulting in a remainder of 5.
The number 3 becomes the next digit in our result. 
Result so far: 42880.733
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.

In conclusion, the division gives 42880.733 with a balance of 0.0005.