We're dividing 645121 by 51 
The aim is to understand the frequency of 51 in 645121.

Let's proceed to step 1:
51 goes into 6 0 times with a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 51

Let's proceed to step 2:
64 divided by 51 is 1 with a remainder of 13.
Write down 1 as next digit of the result. 
Result so far: 1.0
If we subtract 51 from 64, we get 13.
Take the next digit (5) from the dividend and append it to 13, then repeat: 135 / 51

Going ahead to step 3:
51 goes into 135 2 times with a remainder of 33.
Put 2 as the next digit of the answer. 
Result so far: 12.0
If we take 102 away from 135, we end up with 33.
Include the next digit (1) from the dividend after 33, then repeat: 331 / 51

Going ahead to step 4:
51 goes into 331 6 times with a remainder of 25.
Put 6 as the next digit of the answer. 
Result so far: 126.0
If we take 306 away from 331, we end up with 25.
Grab the next digit (2) from the dividend, add it to 25, then carry on: 252 / 51

Step 5:
51 can be fit into 252 4 times, resulting in a remainder of 48.
The number 4 becomes the next digit in our result. 
Result so far: 1264.0
Deduct 204 from 252 and we're left with 48.
Bring next digit (1) of the dividend behind the 48 and repeat the process: 481 / 51

Moving on to step 6:
51 can be fit into 481 9 times, resulting in a remainder of 22.
Use 9 as the next digit of our solution. 
Result so far: 12649.0
Subtracting 459 from 481 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 7:
If we divide 220 by 51, we get 4 and a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 12649.4
Deduct 204 from 220 and we're left with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Step 8:
51 goes into 160 3 times with a remainder of 7.
Write down 3 as next digit of the result. 
Result so far: 12649.43
The remainder is 7 after subtracting 153 from 160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

On to step 9:
If we divide 70 by 51, we get 1 and a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 12649.431
If we take 51 away from 70, we end up with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Going ahead to step 10:
When dividing 190 by 51, we get 3 with a remainder of 37.
Record the quotient 3 as the next digit in the result. 
Result so far: 12649.4313
Subtracting 153 from 190 leaves us with 37.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

Moving on to step 11:
370 divided by 51 is 7 with a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 12649.43137
The remainder is 13 after subtracting 357 from 370.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Advancing to step 12:
When dividing 130 by 51, we get 2 with a remainder of 28.
Record the quotient 2 as the next digit in the result. 
Result so far: 12649.431372
Deduct 102 from 130 and we're left with 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Moving on to step 13:
51 can be fit into 280 5 times, resulting in a remainder of 25.
Write down 5 as next digit of the result. 
Result so far: 12649.4313725
If we subtract 255 from 280, we get 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Advancing to step 14:
The number 51 fits into 250 4 times, leaving a remainder of 46.
The number 4 becomes the next digit in our result. 
Result so far: 12649.43137254
Subtracting 204 from 250 leaves us with 46.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

After the division, we end up with 12649.43137254 and a remainder of 4.6e-08.