644760 ÷ 20 
The aim is to understand the frequency of 20 in 644760.

Moving on to step 1:
When dividing 6 by 20, we get 0 with 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.
Fetch the next digit (4) from the dividend, attach it to 6 and continue: 64 / 20

Step 2:
When dividing 64 by 20, we get 3 with a remainder of 4.
The next digit of our result is 3. 
Result so far: 3.0
Subtract 60 from 64 to get 4.
Take the next digit (4) from the dividend and append it to 4, then repeat: 44 / 20

Advancing to step 3:
The number 20 fits into 44 2 times, leaving a remainder of 4.
Record the quotient 2 as the next digit in the result. 
Result so far: 32.0
If we take 40 away from 44, we end up with 4.
Include the next digit (7) from the dividend after 4, then repeat: 47 / 20

Advancing to step 4:
20 can be fit into 47 2 times, resulting in a remainder of 7.
Write down 2 as next digit of the result. 
Result so far: 322.0
If we take 40 away from 47, we end up with 7.
Include the next digit (6) from the dividend after 7, then repeat: 76 / 20

Moving on to step 5:
When dividing 76 by 20, we get 3 with a remainder of 16.
Record the quotient 3 as the next digit in the result. 
Result so far: 3223.0
The remainder is 16 after subtracting 60 from 76.
Append the next digit (0) from the dividend to 16 and continue with: 160 / 20

Let's proceed to step 6:
160 divided by 20 is 8 with a remainder of 0.
Put 8 as the next digit of the answer. 
Result so far: 32238.0
Deduct 160 from 160 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 7:
20 can be fit into 0 0 times, resulting in a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 32238.0
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 8:
When dividing 0 by 20, we get 0 with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 32238.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The quotient of the division is 32238.0, and the remainder is 0.0.