We divide 643120 by 13
The aim is to understand the frequency of 13 in 643120.

Moving on to step 1:
If we divide 6 by 13, we get 0 and a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 13

Step 2:
13 goes into 64 4 times with a remainder of 12.
The next digit of our result is 4. 
Result so far: 4.0
If we take 52 away from 64, we end up with 12.
Include the next digit (3) from the dividend after 12, then repeat: 123 / 13

Moving on to step 3:
123 divided by 13 is 9 with a remainder of 6.
The number 9 becomes the next digit in our result. 
Result so far: 49.0
If we take 117 away from 123, we end up with 6.
Include the next digit (1) from the dividend after 6, then repeat: 61 / 13

Moving on to step 4:
If we divide 61 by 13, we get 4 and a remainder of 9.
Put 4 as the next digit of the answer. 
Result so far: 494.0
Subtracting 52 from 61 leaves us with 9.
Grab the next digit (2) from the dividend, add it to 9, then carry on: 92 / 13

On to step 5:
92 divided by 13 is 7 with a remainder of 1.
Record the quotient 7 as the next digit in the result. 
Result so far: 4947.0
If we take 91 away from 92, we end up with 1.
Bring next digit (0) of the dividend behind the 1 and repeat the process: 10 / 13

Step 6:
The number 13 fits into 10 0 times, leaving a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 49470.0
Subtract 0 from 10 to get 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 7:
The number 13 fits into 100 7 times, leaving a remainder of 9.
Use 7 as the next digit of our solution. 
Result so far: 49470.7
If we take 91 away from 100, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 8:
The number 13 fits into 90 6 times, leaving a remainder of 12.
The next digit of our result is 6. 
Result so far: 49470.76
If we take 78 away from 90, we end up with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 9:
13 can be fit into 120 9 times, resulting in a remainder of 3.
Use 9 as the next digit of our solution. 
Result so far: 49470.769
Deduct 117 from 120 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

On to step 10:
The number 13 fits into 30 2 times, leaving a remainder of 4.
Write down 2 as next digit of the result. 
Result so far: 49470.7692
The remainder is 4 after subtracting 26 from 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 11:
When dividing 40 by 13, we get 3 with a remainder of 1.
The number 3 becomes the next digit in our result. 
Result so far: 49470.76923
The remainder is 1 after subtracting 39 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Let's proceed to step 12:
If we divide 10 by 13, we get 0 and a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 49470.76923
Deduct 0 from 10 and we're left 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:
When dividing 100 by 13, we get 7 with a remainder of 9.
The next digit of our result is 7. 
Result so far: 49470.7692307
Subtract 91 from 100 to get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Step 14:
13 goes into 90 6 times with a remainder of 12.
The next digit of our result is 6. 
Result so far: 49470.76923076
Deduct 78 from 90 and we're left with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

The quotient of the division is 49470.76923076, and the remainder is 1.2e-08.