We look at the division of 51258623 by 171 
The aim is to understand the frequency of 171 in 51258623.

Advancing to step 1:
If we divide 5 by 171, we get 0 and a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 5 after subtracting 0 from 5.
Grab the next digit (1) from the dividend, add it to 5, then carry on: 51 / 171

Let's proceed to step 2:
171 can be fit into 51 0 times, resulting in a remainder of 51.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 51 after subtracting 0 from 51.
Include the next digit (2) from the dividend after 51, then repeat: 512 / 171

Going ahead to step 3:
512 divided by 171 is 2 with a remainder of 170.
Write down 2 as next digit of the result. 
Result so far: 2.0
Deduct 342 from 512 and we're left with 170.
Take the next digit (5) from the dividend and append it to 170, then repeat: 1705 / 171

Going ahead to step 4:
If we divide 1705 by 171, we get 9 and a remainder of 166.
The number 9 becomes the next digit in our result. 
Result so far: 29.0
Deduct 1539 from 1705 and we're left with 166.
Take the next digit (8) from the dividend and append it to 166, then repeat: 1668 / 171

On to step 5:
The number 171 fits into 1668 9 times, leaving a remainder of 129.
The next digit of our result is 9. 
Result so far: 299.0
If we subtract 1539 from 1668, we get 129.
Fetch the next digit (6) from the dividend, attach it to 129 and continue: 1296 / 171

Let's proceed to step 6:
When dividing 1296 by 171, we get 7 with a remainder of 99.
Record the quotient 7 as the next digit in the result. 
Result so far: 2997.0
If we subtract 1197 from 1296, we get 99.
Fetch the next digit (2) from the dividend, attach it to 99 and continue: 992 / 171

Step 7:
992 divided by 171 is 5 with a remainder of 137.
The number 5 becomes the next digit in our result. 
Result so far: 29975.0
Deduct 855 from 992 and we're left with 137.
Bring next digit (3) of the dividend behind the 137 and repeat the process: 1373 / 171

Step 8:
1373 divided by 171 is 8 with a remainder of 5.
Put 8 as the next digit of the answer. 
Result so far: 299758.0
If we take 1368 away from 1373, we end up with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Advancing to step 9:
50 divided by 171 is 0 with a remainder of 50.
Write down 0 as next digit of the result. 
Result so far: 299758.0
The remainder is 50 after subtracting 0 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Let's proceed to step 10:
171 can be fit into 500 2 times, resulting in a remainder of 158.
Use 2 as the next digit of our solution. 
Result so far: 299758.02
If we take 342 away from 500, we end up with 158.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1580, and continue the process.

Going ahead to step 11:
1580 divided by 171 is 9 with a remainder of 41.
Record the quotient 9 as the next digit in the result. 
Result so far: 299758.029
If we subtract 1539 from 1580, we get 41.
Since there are no more digits in the dividend, we add a zero to the remainder making it 410, and continue the process.

On to step 12:
The number 171 fits into 410 2 times, leaving a remainder of 68.
Record the quotient 2 as the next digit in the result. 
Result so far: 299758.0292
The remainder is 68 after subtracting 342 from 410.
Since there are no more digits in the dividend, we add a zero to the remainder making it 680, and continue the process.

Going ahead to step 13:
680 divided by 171 is 3 with a remainder of 167.
Put 3 as the next digit of the answer. 
Result so far: 299758.02923
Subtract 513 from 680 to get 167.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1670, and continue the process.

Let's proceed to step 14:
If we divide 1670 by 171, we get 9 and a remainder of 131.
Write down 9 as next digit of the result. 
Result so far: 299758.029239
Subtract 1539 from 1670 to get 131.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1310, and continue the process.

Step 15:
The number 171 fits into 1310 7 times, leaving a remainder of 113.
Record the quotient 7 as the next digit in the result. 
Result so far: 299758.0292397
If we subtract 1197 from 1310, we get 113.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1130, and continue the process.

Let's proceed to step 16:
The number 171 fits into 1130 6 times, leaving a remainder of 104.
The number 6 becomes the next digit in our result. 
Result so far: 299758.02923976
Subtracting 1026 from 1130 leaves us with 104.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1040, and continue the process.

After the division, we end up with 299758.02923976 and a remainder of 1.04e-07.