643318 ÷ 39 
The aim is to understand the frequency of 39 in 643318.

Step 1:
39 can be fit into 6 0 times, resulting in a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Fetch the next digit (4) from the dividend, attach it to 6 and continue: 64 / 39

On to step 2:
When dividing 64 by 39, we get 1 with a remainder of 25.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
The remainder is 25 after subtracting 39 from 64.
Fetch the next digit (3) from the dividend, attach it to 25 and continue: 253 / 39

Step 3:
If we divide 253 by 39, we get 6 and a remainder of 19.
Use 6 as the next digit of our solution. 
Result so far: 16.0
Subtracting 234 from 253 leaves us with 19.
Fetch the next digit (3) from the dividend, attach it to 19 and continue: 193 / 39

Advancing to step 4:
If we divide 193 by 39, we get 4 and a remainder of 37.
Record the quotient 4 as the next digit in the result. 
Result so far: 164.0
If we subtract 156 from 193, we get 37.
Fetch the next digit (1) from the dividend, attach it to 37 and continue: 371 / 39

On to step 5:
When dividing 371 by 39, we get 9 with a remainder of 20.
The number 9 becomes the next digit in our result. 
Result so far: 1649.0
Deduct 351 from 371 and we're left with 20.
Grab the next digit (8) from the dividend, add it to 20, then carry on: 208 / 39

Going ahead to step 6:
When dividing 208 by 39, we get 5 with a remainder of 13.
Record the quotient 5 as the next digit in the result. 
Result so far: 16495.0
If we subtract 195 from 208, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Advancing to step 7:
130 divided by 39 is 3 with a remainder of 13.
Record the quotient 3 as the next digit in the result. 
Result so far: 16495.3
The remainder is 13 after subtracting 117 from 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Step 8:
When dividing 130 by 39, we get 3 with a remainder of 13.
Put 3 as the next digit of the answer. 
Result so far: 16495.33
Deduct 117 from 130 and we're left with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

The quotient of the division is 16495.33, and the remainder is 0.013.