We divide 628644 by 15
The aim is to understand the frequency of 15 in 628644.

Moving on to step 1:
15 goes into 6 0 times with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Grab the next digit (2) from the dividend, add it to 6, then carry on: 62 / 15

Advancing to step 2:
15 can be fit into 62 4 times, resulting in a remainder of 2.
Write down 4 as next digit of the result. 
Result so far: 4.0
Subtract 60 from 62 to get 2.
Grab the next digit (8) from the dividend, add it to 2, then carry on: 28 / 15

On to step 3:
15 can be fit into 28 1 times, resulting in a remainder of 13.
Put 1 as the next digit of the answer. 
Result so far: 41.0
Subtract 15 from 28 to get 13.
Append the next digit (6) from the dividend to 13 and continue with: 136 / 15

On to step 4:
If we divide 136 by 15, we get 9 and a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 419.0
If we take 135 away from 136, we end up with 1.
Include the next digit (4) from the dividend after 1, then repeat: 14 / 15

Step 5:
15 goes into 14 0 times with a remainder of 14.
Put 0 as the next digit of the answer. 
Result so far: 4190.0
Deduct 0 from 14 and we're left with 14.
Take the next digit (4) from the dividend and append it to 14, then repeat: 144 / 15

Let's proceed to step 6:
If we divide 144 by 15, we get 9 and a remainder of 9.
The next digit of our result is 9. 
Result so far: 41909.0
Subtract 135 from 144 to get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Let's proceed to step 7:
90 divided by 15 is 6 with a remainder of 0.
Record the quotient 6 as the next digit in the result. 
Result so far: 41909.6
Subtract 90 from 90 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.

Let's proceed to step 8:
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: 41909.6
If we take 0 away from 0, 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 9:
0 divided by 15 is 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 41909.6
If we subtract 0 from 0, we 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.

The final result is 41909.6 with a remainder of 0.0.