521330 ÷ 39 
The aim is to understand the frequency of 39 in 521330.

On to step 1:
39 can be fit into 5 0 times, resulting in a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 5 and we're left with 5.
Include the next digit (2) from the dividend after 5, then repeat: 52 / 39

Step 2:
39 can be fit into 52 1 times, resulting in a remainder of 13.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Subtract 39 from 52 to get 13.
Grab the next digit (1) from the dividend, add it to 13, then carry on: 131 / 39

Let's proceed to step 3:
If we divide 131 by 39, we get 3 and a remainder of 14.
The next digit of our result is 3. 
Result so far: 13.0
Deduct 117 from 131 and we're left with 14.
Append the next digit (3) from the dividend to 14 and continue with: 143 / 39

Going ahead to step 4:
If we divide 143 by 39, we get 3 and a remainder of 26.
Put 3 as the next digit of the answer. 
Result so far: 133.0
If we take 117 away from 143, we end up with 26.
Fetch the next digit (3) from the dividend, attach it to 26 and continue: 263 / 39

Going ahead to step 5:
If we divide 263 by 39, we get 6 and a remainder of 29.
Put 6 as the next digit of the answer. 
Result so far: 1336.0
If we subtract 234 from 263, we get 29.
Take the next digit (0) from the dividend and append it to 29, then repeat: 290 / 39

Moving on to step 6:
If we divide 290 by 39, we get 7 and a remainder of 17.
Put 7 as the next digit of the answer. 
Result so far: 13367.0
If we subtract 273 from 290, we get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Going ahead to step 7:
If we divide 170 by 39, we get 4 and a remainder of 14.
Put 4 as the next digit of the answer. 
Result so far: 13367.4
Subtract 156 from 170 to get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Let's proceed to step 8:
39 goes into 140 3 times with a remainder of 23.
Put 3 as the next digit of the answer. 
Result so far: 13367.43
Subtracting 117 from 140 leaves us with 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

Let's proceed to step 9:
If we divide 230 by 39, we get 5 and a remainder of 35.
The next digit of our result is 5. 
Result so far: 13367.435
Subtracting 195 from 230 leaves us with 35.
Since there are no more digits in the dividend, we add a zero to the remainder making it 350, and continue the process.

Moving on to step 10:
39 can be fit into 350 8 times, resulting in a remainder of 38.
Put 8 as the next digit of the answer. 
Result so far: 13367.4358
Subtract 312 from 350 to get 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Going ahead to step 11:
If we divide 380 by 39, we get 9 and a remainder of 29.
Write down 9 as next digit of the result. 
Result so far: 13367.43589
Deduct 351 from 380 and we're left with 29.
Since there are no more digits in the dividend, we add a zero to the remainder making it 290, and continue the process.

Advancing to step 12:
39 goes into 290 7 times with a remainder of 17.
The next digit of our result is 7. 
Result so far: 13367.435897
If we subtract 273 from 290, we get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Let's proceed to step 13:
If we divide 170 by 39, we get 4 and a remainder of 14.
Record the quotient 4 as the next digit in the result. 
Result so far: 13367.4358974
Subtract 156 from 170 to get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Moving on to step 14:
The number 39 fits into 140 3 times, leaving a remainder of 23.
Record the quotient 3 as the next digit in the result. 
Result so far: 13367.43589743
If we subtract 117 from 140, we get 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

The final result is 13367.43589743 with a remainder of 2.3e-08.