We look at the division of 13493506 by 521 
The aim is to understand the frequency of 521 in 13493506.

Moving on to step 1:
521 goes into 1 0 times with a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Take the next digit (3) from the dividend and append it to 1, then repeat: 13 / 521

Moving on to step 2:
The number 521 fits into 13 0 times, leaving a remainder of 13.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 13 after subtracting 0 from 13.
Append the next digit (4) from the dividend to 13 and continue with: 134 / 521

Step 3:
521 can be fit into 134 0 times, resulting in a remainder of 134.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 134 and we're left with 134.
Append the next digit (9) from the dividend to 134 and continue with: 1349 / 521

Let's proceed to step 4:
If we divide 1349 by 521, we get 2 and a remainder of 307.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
The remainder is 307 after subtracting 1042 from 1349.
Bring next digit (3) of the dividend behind the 307 and repeat the process: 3073 / 521

Going ahead to step 5:
3073 divided by 521 is 5 with a remainder of 468.
Use 5 as the next digit of our solution. 
Result so far: 25.0
Subtract 2605 from 3073 to get 468.
Fetch the next digit (5) from the dividend, attach it to 468 and continue: 4685 / 521

Advancing to step 6:
521 goes into 4685 8 times with a remainder of 517.
Record the quotient 8 as the next digit in the result. 
Result so far: 258.0
Subtract 4168 from 4685 to get 517.
Fetch the next digit (0) from the dividend, attach it to 517 and continue: 5170 / 521

On to step 7:
When dividing 5170 by 521, we get 9 with a remainder of 481.
Write down 9 as next digit of the result. 
Result so far: 2589.0
Subtracting 4689 from 5170 leaves us with 481.
Include the next digit (6) from the dividend after 481, then repeat: 4816 / 521

Step 8:
When dividing 4816 by 521, we get 9 with a remainder of 127.
Record the quotient 9 as the next digit in the result. 
Result so far: 25899.0
Deduct 4689 from 4816 and we're left with 127.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1270, and continue the process.

Let's proceed to step 9:
521 can be fit into 1270 2 times, resulting in a remainder of 228.
Put 2 as the next digit of the answer. 
Result so far: 25899.2
Subtract 1042 from 1270 to get 228.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2280, and continue the process.

Advancing to step 10:
The number 521 fits into 2280 4 times, leaving a remainder of 196.
Put 4 as the next digit of the answer. 
Result so far: 25899.24
The remainder is 196 after subtracting 2084 from 2280.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1960, and continue the process.

On to step 11:
The number 521 fits into 1960 3 times, leaving a remainder of 397.
Write down 3 as next digit of the result. 
Result so far: 25899.243
Deduct 1563 from 1960 and we're left with 397.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3970, and continue the process.

Let's proceed to step 12:
If we divide 3970 by 521, we get 7 and a remainder of 323.
Put 7 as the next digit of the answer. 
Result so far: 25899.2437
If we subtract 3647 from 3970, we get 323.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3230, and continue the process.

Let's proceed to step 13:
When dividing 3230 by 521, we get 6 with a remainder of 104.
The number 6 becomes the next digit in our result. 
Result so far: 25899.24376
Subtract 3126 from 3230 to get 104.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1040, and continue the process.

Step 14:
When dividing 1040 by 521, we get 1 with a remainder of 519.
Use 1 as the next digit of our solution. 
Result so far: 25899.243761
Deduct 521 from 1040 and we're left with 519.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5190, and continue the process.

Advancing to step 15:
521 goes into 5190 9 times with a remainder of 501.
The number 9 becomes the next digit in our result. 
Result so far: 25899.2437619
The remainder is 501 after subtracting 4689 from 5190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5010, and continue the process.

Moving on to step 16:
521 can be fit into 5010 9 times, resulting in a remainder of 321.
Use 9 as the next digit of our solution. 
Result so far: 25899.24376199
Deduct 4689 from 5010 and we're left with 321.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3210, and continue the process.

After the division, we end up with 25899.24376199 and a remainder of 3.21e-07.