12970913 divided by 643 
The aim is to understand the frequency of 643 in 12970913.

Going ahead to step 1:
The number 643 fits into 1 0 times, leaving a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Take the next digit (2) from the dividend and append it to 1, then repeat: 12 / 643

Step 2:
When dividing 12 by 643, we get 0 with a remainder of 12.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 12 and we're left with 12.
Take the next digit (9) from the dividend and append it to 12, then repeat: 129 / 643

Step 3:
When dividing 129 by 643, we get 0 with a remainder of 129.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 129 and we're left with 129.
Bring next digit (7) of the dividend behind the 129 and repeat the process: 1297 / 643

Going ahead to step 4:
643 goes into 1297 2 times with a remainder of 11.
Put 2 as the next digit of the answer. 
Result so far: 2.0
The remainder is 11 after subtracting 1286 from 1297.
Fetch the next digit (0) from the dividend, attach it to 11 and continue: 110 / 643

Step 5:
When dividing 110 by 643, we get 0 with a remainder of 110.
The number 0 becomes the next digit in our result. 
Result so far: 20.0
Deduct 0 from 110 and we're left with 110.
Fetch the next digit (9) from the dividend, attach it to 110 and continue: 1109 / 643

Going ahead to step 6:
643 can be fit into 1109 1 times, resulting in a remainder of 466.
The next digit of our result is 1. 
Result so far: 201.0
The remainder is 466 after subtracting 643 from 1109.
Grab the next digit (1) from the dividend, add it to 466, then carry on: 4661 / 643

Let's proceed to step 7:
If we divide 4661 by 643, we get 7 and a remainder of 160.
Write down 7 as next digit of the result. 
Result so far: 2017.0
The remainder is 160 after subtracting 4501 from 4661.
Include the next digit (3) from the dividend after 160, then repeat: 1603 / 643

On to step 8:
1603 divided by 643 is 2 with a remainder of 317.
Record the quotient 2 as the next digit in the result. 
Result so far: 20172.0
The remainder is 317 after subtracting 1286 from 1603.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3170, and continue the process.

Advancing to step 9:
643 can be fit into 3170 4 times, resulting in a remainder of 598.
Put 4 as the next digit of the answer. 
Result so far: 20172.4
If we subtract 2572 from 3170, we get 598.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5980, and continue the process.

Moving on to step 10:
When dividing 5980 by 643, we get 9 with a remainder of 193.
Record the quotient 9 as the next digit in the result. 
Result so far: 20172.49
Subtracting 5787 from 5980 leaves us with 193.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1930, and continue the process.

Let's proceed to step 11:
643 goes into 1930 3 times with a remainder of 1.
The number 3 becomes the next digit in our result. 
Result so far: 20172.493
Subtracting 1929 from 1930 leaves us with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 12:
If we divide 10 by 643, we get 0 and a remainder of 10.
The next digit of our result is 0. 
Result so far: 20172.493
Subtracting 0 from 10 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 13:
The number 643 fits into 100 0 times, leaving a remainder of 100.
Write down 0 as next digit of the result. 
Result so far: 20172.493
The remainder is 100 after subtracting 0 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1000, and continue the process.

After the division, we end up with 20172.493 and a remainder of 0.0001.