643949 ÷ 43 
The aim is to understand the frequency of 43 in 643949.

Let's proceed to step 1:
43 goes into 6 0 times with a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Take the next digit (4) from the dividend and append it to 6, then repeat: 64 / 43

Let's proceed to step 2:
43 can be fit into 64 1 times, resulting in a remainder of 21.
Write down 1 as next digit of the result. 
Result so far: 1.0
Deduct 43 from 64 and we're left with 21.
Fetch the next digit (3) from the dividend, attach it to 21 and continue: 213 / 43

Let's proceed to step 3:
When dividing 213 by 43, we get 4 with a remainder of 41.
Record the quotient 4 as the next digit in the result. 
Result so far: 14.0
Subtract 172 from 213 to get 41.
Fetch the next digit (9) from the dividend, attach it to 41 and continue: 419 / 43

On to step 4:
When dividing 419 by 43, we get 9 with a remainder of 32.
The next digit of our result is 9. 
Result so far: 149.0
Deduct 387 from 419 and we're left with 32.
Bring next digit (4) of the dividend behind the 32 and repeat the process: 324 / 43

On to step 5:
324 divided by 43 is 7 with a remainder of 23.
The number 7 becomes the next digit in our result. 
Result so far: 1497.0
If we take 301 away from 324, we end up with 23.
Bring next digit (9) of the dividend behind the 23 and repeat the process: 239 / 43

Let's proceed to step 6:
43 can be fit into 239 5 times, resulting in a remainder of 24.
The number 5 becomes the next digit in our result. 
Result so far: 14975.0
The remainder is 24 after subtracting 215 from 239.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Going ahead to step 7:
43 goes into 240 5 times with a remainder of 25.
The next digit of our result is 5. 
Result so far: 14975.5
If we take 215 away from 240, we end up with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

On to step 8:
If we divide 250 by 43, we get 5 and a remainder of 35.
The number 5 becomes the next digit in our result. 
Result so far: 14975.55
If we subtract 215 from 250, we get 35.
Since there are no more digits in the dividend, we add a zero to the remainder making it 350, and continue the process.

After the division, we end up with 14975.55 and a remainder of 0.035.