We're dividing 36951801 by 521 
The aim is to understand the frequency of 521 in 36951801.

On to step 1:
521 can be fit into 3 0 times, resulting in a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Append the next digit (6) from the dividend to 3 and continue with: 36 / 521

Step 2:
521 goes into 36 0 times with a remainder of 36.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 36 leaves us with 36.
Fetch the next digit (9) from the dividend, attach it to 36 and continue: 369 / 521

Moving on to step 3:
The number 521 fits into 369 0 times, leaving a remainder of 369.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 369 and we're left with 369.
Include the next digit (5) from the dividend after 369, then repeat: 3695 / 521

Advancing to step 4:
521 goes into 3695 7 times with a remainder of 48.
Put 7 as the next digit of the answer. 
Result so far: 7.0
Subtract 3647 from 3695 to get 48.
Take the next digit (1) from the dividend and append it to 48, then repeat: 481 / 521

Going ahead to step 5:
521 can be fit into 481 0 times, resulting in a remainder of 481.
Write down 0 as next digit of the result. 
Result so far: 70.0
The remainder is 481 after subtracting 0 from 481.
Grab the next digit (8) from the dividend, add it to 481, then carry on: 4818 / 521

Advancing to step 6:
4818 divided by 521 is 9 with a remainder of 129.
Put 9 as the next digit of the answer. 
Result so far: 709.0
Deduct 4689 from 4818 and we're left with 129.
Include the next digit (0) from the dividend after 129, then repeat: 1290 / 521

Advancing to step 7:
If we divide 1290 by 521, we get 2 and a remainder of 248.
The number 2 becomes the next digit in our result. 
Result so far: 7092.0
Subtract 1042 from 1290 to get 248.
Grab the next digit (1) from the dividend, add it to 248, then carry on: 2481 / 521

Step 8:
When dividing 2481 by 521, we get 4 with a remainder of 397.
The number 4 becomes the next digit in our result. 
Result so far: 70924.0
If we subtract 2084 from 2481, we get 397.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3970, and continue the process.

Going ahead to step 9:
If we divide 3970 by 521, we get 7 and a remainder of 323.
Write down 7 as next digit of the result. 
Result so far: 70924.7
Subtracting 3647 from 3970 leaves us with 323.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3230, and continue the process.

Moving on to step 10:
When dividing 3230 by 521, we get 6 with a remainder of 104.
Put 6 as the next digit of the answer. 
Result so far: 70924.76
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 11:
The number 521 fits into 1040 1 times, leaving a remainder of 519.
Record the quotient 1 as the next digit in the result. 
Result so far: 70924.761
Subtracting 521 from 1040 leaves us 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.

Step 12:
5190 divided by 521 is 9 with a remainder of 501.
Record the quotient 9 as the next digit in the result. 
Result so far: 70924.7619
If we take 4689 away from 5190, we end up with 501.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5010, and continue the process.

On to step 13:
521 goes into 5010 9 times with a remainder of 321.
Put 9 as the next digit of the answer. 
Result so far: 70924.76199
If we take 4689 away from 5010, we end up 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.

The final result is 70924.76199 with a remainder of 0.000321.