We divide 40720 by 3
The aim is to understand the frequency of 3 in 40720.

Going ahead to step 1:
3 goes into 4 1 times with a remainder of 1.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtracting 3 from 4 leaves us with 1.
Include the next digit (0) from the dividend after 1, then repeat: 10 / 3

Step 2:
3 goes into 10 3 times with a remainder of 1.
The number 3 becomes the next digit in our result. 
Result so far: 13.0
If we subtract 9 from 10, we get 1.
Fetch the next digit (7) from the dividend, attach it to 1 and continue: 17 / 3

Advancing to step 3:
17 divided by 3 is 5 with a remainder of 2.
The number 5 becomes the next digit in our result. 
Result so far: 135.0
If we take 15 away from 17, we end up with 2.
Bring next digit (2) of the dividend behind the 2 and repeat the process: 22 / 3

Moving on to step 4:
22 divided by 3 is 7 with a remainder of 1.
The next digit of our result is 7. 
Result so far: 1357.0
The remainder is 1 after subtracting 21 from 22.
Take the next digit (0) from the dividend and append it to 1, then repeat: 10 / 3

Advancing to step 5:
3 goes into 10 3 times with a remainder of 1.
Write down 3 as next digit of the result. 
Result so far: 13573.0
If we subtract 9 from 10, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 6:
3 can be fit into 10 3 times, resulting in a remainder of 1.
Write down 3 as next digit of the result. 
Result so far: 13573.3
Subtracting 9 from 10 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.

Let's proceed to step 7:
3 can be fit into 10 3 times, resulting in a remainder of 1.
The next digit of our result is 3. 
Result so far: 13573.33
Subtracting 9 from 10 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.

The final result is 13573.33 with a remainder of 0.001.