We divide 403607 by 15
The aim is to understand the frequency of 15 in 403607.

Going ahead to step 1:
The number 15 fits into 4 0 times, leaving a remainder of 4.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 4 leaves us with 4.
Grab the next digit (0) from the dividend, add it to 4, then carry on: 40 / 15

Advancing to step 2:
The number 15 fits into 40 2 times, leaving a remainder of 10.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Subtracting 30 from 40 leaves us with 10.
Bring next digit (3) of the dividend behind the 10 and repeat the process: 103 / 15

Let's proceed to step 3:
The number 15 fits into 103 6 times, leaving a remainder of 13.
Use 6 as the next digit of our solution. 
Result so far: 26.0
If we subtract 90 from 103, we get 13.
Append the next digit (6) from the dividend to 13 and continue with: 136 / 15

On to step 4:
When dividing 136 by 15, we get 9 with a remainder of 1.
The next digit of our result is 9. 
Result so far: 269.0
Deduct 135 from 136 and we're left with 1.
Fetch the next digit (0) from the dividend, attach it to 1 and continue: 10 / 15

Let's proceed to step 5:
When dividing 10 by 15, we get 0 with a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 2690.0
If we take 0 away from 10, we end up with 10.
Include the next digit (7) from the dividend after 10, then repeat: 107 / 15

Step 6:
15 goes into 107 7 times with a remainder of 2.
Put 7 as the next digit of the answer. 
Result so far: 26907.0
If we subtract 105 from 107, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 7:
15 goes into 20 1 times with a remainder of 5.
The number 1 becomes the next digit in our result. 
Result so far: 26907.1
Deduct 15 from 20 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.

Moving on to step 8:
If we divide 50 by 15, we get 3 and a remainder of 5.
Put 3 as the next digit of the answer. 
Result so far: 26907.13
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.

Advancing to step 9:
When dividing 50 by 15, we get 3 with a remainder of 5.
Record the quotient 3 as the next digit in the result. 
Result so far: 26907.133
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.

The quotient of the division is 26907.133, and the remainder is 0.0005.