726173 ÷ 15 
The aim is to understand the frequency of 15 in 726173.

Step 1:
7 divided by 15 is 0 with a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 7 leaves us with 7.
Append the next digit (2) from the dividend to 7 and continue with: 72 / 15

Going ahead to step 2:
15 can be fit into 72 4 times, resulting in a remainder of 12.
Put 4 as the next digit of the answer. 
Result so far: 4.0
If we take 60 away from 72, we end up with 12.
Bring next digit (6) of the dividend behind the 12 and repeat the process: 126 / 15

Step 3:
If we divide 126 by 15, we get 8 and a remainder of 6.
Record the quotient 8 as the next digit in the result. 
Result so far: 48.0
Subtract 120 from 126 to get 6.
Bring next digit (1) of the dividend behind the 6 and repeat the process: 61 / 15

Going ahead to step 4:
If we divide 61 by 15, we get 4 and a remainder of 1.
The number 4 becomes the next digit in our result. 
Result so far: 484.0
The remainder is 1 after subtracting 60 from 61.
Take the next digit (7) from the dividend and append it to 1, then repeat: 17 / 15

Going ahead to step 5:
15 can be fit into 17 1 times, resulting in a remainder of 2.
Write down 1 as next digit of the result. 
Result so far: 4841.0
The remainder is 2 after subtracting 15 from 17.
Bring next digit (3) of the dividend behind the 2 and repeat the process: 23 / 15

Step 6:
15 goes into 23 1 times with a remainder of 8.
Record the quotient 1 as the next digit in the result. 
Result so far: 48411.0
Deduct 15 from 23 and we're left with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 7:
15 goes into 80 5 times with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 48411.5
Subtract 75 from 80 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.

On to step 8:
15 goes into 50 3 times with a remainder of 5.
The number 3 becomes the next digit in our result. 
Result so far: 48411.53
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.
Use 3 as the next digit of our solution. 
Result so far: 48411.533
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.

Our division results in 48411.533 with a remaining 0.0005.