903428 ÷ 15 
The aim is to understand the frequency of 15 in 903428.

On to step 1:
The number 15 fits into 9 0 times, leaving a remainder of 9.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 9 and we're left with 9.
Append the next digit (0) from the dividend to 9 and continue with: 90 / 15

Going ahead to step 2:
If we divide 90 by 15, we get 6 and a remainder of 0.
Record the quotient 6 as the next digit in the result. 
Result so far: 6.0
Subtract 90 from 90 to get 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 15

Moving on to step 3:
When dividing 3 by 15, we get 0 with a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 60.0
Subtracting 0 from 3 leaves us with 3.
Take the next digit (4) from the dividend and append it to 3, then repeat: 34 / 15

Moving on to step 4:
The number 15 fits into 34 2 times, leaving a remainder of 4.
The next digit of our result is 2. 
Result so far: 602.0
Deduct 30 from 34 and we're left with 4.
Append the next digit (2) from the dividend to 4 and continue with: 42 / 15

On to step 5:
The number 15 fits into 42 2 times, leaving a remainder of 12.
The next digit of our result is 2. 
Result so far: 6022.0
If we subtract 30 from 42, we get 12.
Append the next digit (8) from the dividend to 12 and continue with: 128 / 15

Step 6:
15 can be fit into 128 8 times, resulting in a remainder of 8.
Put 8 as the next digit of the answer. 
Result so far: 60228.0
If we take 120 away from 128, we end up 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.

Going ahead to step 7:
When dividing 80 by 15, we get 5 with a remainder of 5.
Use 5 as the next digit of our solution. 
Result so far: 60228.5
Deduct 75 from 80 and we're left 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.

Advancing to step 8:
When dividing 50 by 15, we get 3 with a remainder of 5.
Put 3 as the next digit of the answer. 
Result so far: 60228.53
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 goes into 50 3 times with a remainder of 5.
Use 3 as the next digit of our solution. 
Result so far: 60228.533
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 60228.533 with a remaining 0.0005.