We look at the division of 636587 by 20 
The aim is to understand the frequency of 20 in 636587.

Going ahead to step 1:
20 goes into 6 0 times with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Append the next digit (3) from the dividend to 6 and continue with: 63 / 20

Advancing to step 2:
63 divided by 20 is 3 with a remainder of 3.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
The remainder is 3 after subtracting 60 from 63.
Include the next digit (6) from the dividend after 3, then repeat: 36 / 20

On to step 3:
20 goes into 36 1 times with a remainder of 16.
Put 1 as the next digit of the answer. 
Result so far: 31.0
The remainder is 16 after subtracting 20 from 36.
Include the next digit (5) from the dividend after 16, then repeat: 165 / 20

Moving on to step 4:
20 can be fit into 165 8 times, resulting in a remainder of 5.
The next digit of our result is 8. 
Result so far: 318.0
Subtract 160 from 165 to get 5.
Include the next digit (8) from the dividend after 5, then repeat: 58 / 20

Going ahead to step 5:
58 divided by 20 is 2 with a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 3182.0
Deduct 40 from 58 and we're left with 18.
Append the next digit (7) from the dividend to 18 and continue with: 187 / 20

Moving on to step 6:
20 goes into 187 9 times with a remainder of 7.
The next digit of our result is 9. 
Result so far: 31829.0
If we take 180 away from 187, we end up with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Advancing to step 7:
20 can be fit into 70 3 times, resulting in a remainder of 10.
The next digit of our result is 3. 
Result so far: 31829.3
Subtracting 60 from 70 leaves us 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 8:
The number 20 fits into 100 5 times, leaving a remainder of 0.
Record the quotient 5 as the next digit in the result. 
Result so far: 31829.35
Subtract 100 from 100 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 9:
When dividing 0 by 20, we get 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 31829.35
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 10:
20 can be fit into 0 0 times, resulting in a remainder of 0.
The next digit of our result is 0. 
Result so far: 31829.35
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.

The final outcome is 31829.35, with a leftover of 0.0.