Let's divide 721608 by 15
The aim is to understand the frequency of 15 in 721608.

Going ahead to step 1:
If we divide 7 by 15, we get 0 and a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Bring next digit (2) of the dividend behind the 7 and repeat the process: 72 / 15

Advancing to step 2:
The number 15 fits into 72 4 times, leaving a remainder of 12.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
The remainder is 12 after subtracting 60 from 72.
Fetch the next digit (1) from the dividend, attach it to 12 and continue: 121 / 15

Step 3:
The number 15 fits into 121 8 times, leaving a remainder of 1.
The number 8 becomes the next digit in our result. 
Result so far: 48.0
Deduct 120 from 121 and we're left with 1.
Fetch the next digit (6) from the dividend, attach it to 1 and continue: 16 / 15

On to step 4:
If we divide 16 by 15, we get 1 and a remainder of 1.
Record the quotient 1 as the next digit in the result. 
Result so far: 481.0
If we take 15 away from 16, we end up with 1.
Take the next digit (0) from the dividend and append it to 1, then repeat: 10 / 15

On to step 5:
15 can be fit into 10 0 times, resulting in a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 4810.0
Subtracting 0 from 10 leaves us with 10.
Take the next digit (8) from the dividend and append it to 10, then repeat: 108 / 15

Step 6:
15 goes into 108 7 times with a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 48107.0
Subtract 105 from 108 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 7:
15 goes into 30 2 times with a remainder of 0.
Use 2 as the next digit of our solution. 
Result so far: 48107.2
The remainder is 0 after subtracting 30 from 30.
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:
15 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 48107.2
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 9:
When dividing 0 by 15, we get 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 48107.2
Subtracting 0 from 0 leaves us 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.

After the division, we end up with 48107.2 and a remainder of 0.0.