8259507 divided by 521 
The aim is to understand the frequency of 521 in 8259507.

On to step 1:
If we divide 8 by 521, we get 0 and a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 8, we end up with 8.
Fetch the next digit (2) from the dividend, attach it to 8 and continue: 82 / 521

Let's proceed to step 2:
If we divide 82 by 521, we get 0 and a remainder of 82.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 82 leaves us with 82.
Fetch the next digit (5) from the dividend, attach it to 82 and continue: 825 / 521

Going ahead to step 3:
825 divided by 521 is 1 with a remainder of 304.
The next digit of our result is 1. 
Result so far: 1.0
Deduct 521 from 825 and we're left with 304.
Append the next digit (9) from the dividend to 304 and continue with: 3049 / 521

Step 4:
521 can be fit into 3049 5 times, resulting in a remainder of 444.
Record the quotient 5 as the next digit in the result. 
Result so far: 15.0
If we take 2605 away from 3049, we end up with 444.
Include the next digit (5) from the dividend after 444, then repeat: 4445 / 521

Step 5:
When dividing 4445 by 521, we get 8 with a remainder of 277.
Record the quotient 8 as the next digit in the result. 
Result so far: 158.0
Deduct 4168 from 4445 and we're left with 277.
Grab the next digit (0) from the dividend, add it to 277, then carry on: 2770 / 521

Advancing to step 6:
521 can be fit into 2770 5 times, resulting in a remainder of 165.
Put 5 as the next digit of the answer. 
Result so far: 1585.0
If we subtract 2605 from 2770, we get 165.
Append the next digit (7) from the dividend to 165 and continue with: 1657 / 521

Let's proceed to step 7:
The number 521 fits into 1657 3 times, leaving a remainder of 94.
The number 3 becomes the next digit in our result. 
Result so far: 15853.0
If we take 1563 away from 1657, we end up with 94.
Since there are no more digits in the dividend, we add a zero to the remainder making it 940, and continue the process.

Advancing to step 8:
940 divided by 521 is 1 with a remainder of 419.
The next digit of our result is 1. 
Result so far: 15853.1
If we take 521 away from 940, we end up with 419.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4190, and continue the process.

Going ahead to step 9:
521 goes into 4190 8 times with a remainder of 22.
Use 8 as the next digit of our solution. 
Result so far: 15853.18
Subtracting 4168 from 4190 leaves us with 22.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Let's proceed to step 10:
220 divided by 521 is 0 with a remainder of 220.
The number 0 becomes the next digit in our result. 
Result so far: 15853.18
Subtract 0 from 220 to get 220.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2200, and continue the process.

Moving on to step 11:
The number 521 fits into 2200 4 times, leaving a remainder of 116.
Put 4 as the next digit of the answer. 
Result so far: 15853.1804
Deduct 2084 from 2200 and we're left with 116.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1160, and continue the process.

Going ahead to step 12:
If we divide 1160 by 521, we get 2 and a remainder of 118.
Write down 2 as next digit of the result. 
Result so far: 15853.18042
If we subtract 1042 from 1160, we get 118.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1180, and continue the process.

Moving on to step 13:
The number 521 fits into 1180 2 times, leaving a remainder of 138.
Use 2 as the next digit of our solution. 
Result so far: 15853.180422
Subtract 1042 from 1180 to get 138.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1380, and continue the process.

The quotient of the division is 15853.180422, and the remainder is 1.38e-05.