We look at the division of 12897151 by 813 
The aim is to understand the frequency of 813 in 12897151.

On to step 1:
If we divide 1 by 813, we get 0 and a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 1 and we're left with 1.
Fetch the next digit (2) from the dividend, attach it to 1 and continue: 12 / 813

Moving on to step 2:
813 goes into 12 0 times with a remainder of 12.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 12 after subtracting 0 from 12.
Fetch the next digit (8) from the dividend, attach it to 12 and continue: 128 / 813

Step 3:
813 goes into 128 0 times with a remainder of 128.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 128 after subtracting 0 from 128.
Take the next digit (9) from the dividend and append it to 128, then repeat: 1289 / 813

On to step 4:
813 goes into 1289 1 times with a remainder of 476.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we subtract 813 from 1289, we get 476.
Grab the next digit (7) from the dividend, add it to 476, then carry on: 4767 / 813

Going ahead to step 5:
4767 divided by 813 is 5 with a remainder of 702.
The next digit of our result is 5. 
Result so far: 15.0
If we take 4065 away from 4767, we end up with 702.
Include the next digit (1) from the dividend after 702, then repeat: 7021 / 813

Advancing to step 6:
The number 813 fits into 7021 8 times, leaving a remainder of 517.
Record the quotient 8 as the next digit in the result. 
Result so far: 158.0
If we subtract 6504 from 7021, we get 517.
Include the next digit (5) from the dividend after 517, then repeat: 5175 / 813

On to step 7:
When dividing 5175 by 813, we get 6 with a remainder of 297.
Write down 6 as next digit of the result. 
Result so far: 1586.0
Subtracting 4878 from 5175 leaves us with 297.
Fetch the next digit (1) from the dividend, attach it to 297 and continue: 2971 / 813

Going ahead to step 8:
The number 813 fits into 2971 3 times, leaving a remainder of 532.
The next digit of our result is 3. 
Result so far: 15863.0
Subtracting 2439 from 2971 leaves us with 532.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5320, and continue the process.

Moving on to step 9:
If we divide 5320 by 813, we get 6 and a remainder of 442.
Write down 6 as next digit of the result. 
Result so far: 15863.6
Deduct 4878 from 5320 and we're left with 442.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4420, and continue the process.

Step 10:
If we divide 4420 by 813, we get 5 and a remainder of 355.
Put 5 as the next digit of the answer. 
Result so far: 15863.65
Subtracting 4065 from 4420 leaves us with 355.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3550, and continue the process.

Step 11:
3550 divided by 813 is 4 with a remainder of 298.
The next digit of our result is 4. 
Result so far: 15863.654
The remainder is 298 after subtracting 3252 from 3550.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2980, and continue the process.

Let's proceed to step 12:
813 can be fit into 2980 3 times, resulting in a remainder of 541.
Use 3 as the next digit of our solution. 
Result so far: 15863.6543
Subtracting 2439 from 2980 leaves us with 541.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5410, and continue the process.

On to step 13:
5410 divided by 813 is 6 with a remainder of 532.
Record the quotient 6 as the next digit in the result. 
Result so far: 15863.65436
If we subtract 4878 from 5410, we get 532.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5320, and continue the process.

On to step 14:
5320 divided by 813 is 6 with a remainder of 442.
The number 6 becomes the next digit in our result. 
Result so far: 15863.654366
Deduct 4878 from 5320 and we're left with 442.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4420, and continue the process.

The quotient of the division is 15863.654366, and the remainder is 4.42e-05.