We look at the division of 72371137 by 15 
The aim is to understand the frequency of 15 in 72371137.

On to 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.
Fetch the next digit (2) from the dividend, attach it to 7 and continue: 72 / 15

Step 2:
When dividing 72 by 15, we get 4 with a remainder of 12.
Put 4 as the next digit of the answer. 
Result so far: 4.0
Subtract 60 from 72 to get 12.
Fetch the next digit (3) from the dividend, attach it to 12 and continue: 123 / 15

Step 3:
15 can be fit into 123 8 times, resulting in a remainder of 3.
The number 8 becomes the next digit in our result. 
Result so far: 48.0
Deduct 120 from 123 and we're left with 3.
Include the next digit (7) from the dividend after 3, then repeat: 37 / 15

Going ahead to step 4:
15 can be fit into 37 2 times, resulting in a remainder of 7.
The next digit of our result is 2. 
Result so far: 482.0
Deduct 30 from 37 and we're left with 7.
Fetch the next digit (1) from the dividend, attach it to 7 and continue: 71 / 15

Step 5:
When dividing 71 by 15, we get 4 with a remainder of 11.
Write down 4 as next digit of the result. 
Result so far: 4824.0
Subtracting 60 from 71 leaves us with 11.
Take the next digit (1) from the dividend and append it to 11, then repeat: 111 / 15

Going ahead to step 6:
If we divide 111 by 15, we get 7 and a remainder of 6.
Use 7 as the next digit of our solution. 
Result so far: 48247.0
Deduct 105 from 111 and we're left with 6.
Fetch the next digit (3) from the dividend, attach it to 6 and continue: 63 / 15

Let's proceed to step 7:
The number 15 fits into 63 4 times, leaving a remainder of 3.
The number 4 becomes the next digit in our result. 
Result so far: 482474.0
If we subtract 60 from 63, we get 3.
Take the next digit (7) from the dividend and append it to 3, then repeat: 37 / 15

Advancing to step 8:
If we divide 37 by 15, we get 2 and a remainder of 7.
Write down 2 as next digit of the result. 
Result so far: 4824742.0
Deduct 30 from 37 and we're left with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Going ahead to step 9:
If we divide 70 by 15, we get 4 and a remainder of 10.
Write down 4 as next digit of the result. 
Result so far: 4824742.4
Subtract 60 from 70 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 10:
The number 15 fits into 100 6 times, leaving a remainder of 10.
Record the quotient 6 as the next digit in the result. 
Result so far: 4824742.46
Subtract 90 from 100 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 11:
100 divided by 15 is 6 with a remainder of 10.
The number 6 becomes the next digit in our result. 
Result so far: 4824742.466
Subtracting 90 from 100 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

The final outcome is 4824742.466, with a leftover of 0.001.