We look at the division of 3987724 by 520 
The aim is to understand the frequency of 520 in 3987724.

Step 1:
When dividing 3 by 520, we get 0 with a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Fetch the next digit (9) from the dividend, attach it to 3 and continue: 39 / 520

Step 2:
39 divided by 520 is 0 with a remainder of 39.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 39, we get 39.
Include the next digit (8) from the dividend after 39, then repeat: 398 / 520

Let's proceed to step 3:
398 divided by 520 is 0 with a remainder of 398.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 398 to get 398.
Append the next digit (7) from the dividend to 398 and continue with: 3987 / 520

Moving on to step 4:
If we divide 3987 by 520, we get 7 and a remainder of 347.
Write down 7 as next digit of the result. 
Result so far: 7.0
If we subtract 3640 from 3987, we get 347.
Append the next digit (7) from the dividend to 347 and continue with: 3477 / 520

Step 5:
520 goes into 3477 6 times with a remainder of 357.
Put 6 as the next digit of the answer. 
Result so far: 76.0
If we subtract 3120 from 3477, we get 357.
Include the next digit (2) from the dividend after 357, then repeat: 3572 / 520

Let's proceed to step 6:
If we divide 3572 by 520, we get 6 and a remainder of 452.
Record the quotient 6 as the next digit in the result. 
Result so far: 766.0
Subtract 3120 from 3572 to get 452.
Append the next digit (4) from the dividend to 452 and continue with: 4524 / 520

On to step 7:
If we divide 4524 by 520, we get 8 and a remainder of 364.
The next digit of our result is 8. 
Result so far: 7668.0
Subtract 4160 from 4524 to get 364.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3640, and continue the process.

Step 8:
3640 divided by 520 is 7 with a remainder of 0.
The next digit of our result is 7. 
Result so far: 7668.7
Subtract 3640 from 3640 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.

On to step 9:
When dividing 0 by 520, we get 0 with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 7668.7
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 10:
520 can be fit into 0 0 times, resulting in a remainder of 0.
The next digit of our result is 0. 
Result so far: 7668.7
Deduct 0 from 0 and we're left 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.

In conclusion, the division gives 7668.7 with a balance of 0.0.