Let's divide 639487 by 20
The aim is to understand the frequency of 20 in 639487.

Step 1:
20 goes into 6 0 times with a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Fetch the next digit (3) from the dividend, attach it to 6 and continue: 63 / 20

Advancing to step 2:
20 goes into 63 3 times with a remainder of 3.
The next digit of our result is 3. 
Result so far: 3.0
Deduct 60 from 63 and we're left with 3.
Include the next digit (9) from the dividend after 3, then repeat: 39 / 20

Advancing to step 3:
20 can be fit into 39 1 times, resulting in a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 31.0
Deduct 20 from 39 and we're left with 19.
Fetch the next digit (4) from the dividend, attach it to 19 and continue: 194 / 20

Moving on to step 4:
When dividing 194 by 20, we get 9 with a remainder of 14.
Put 9 as the next digit of the answer. 
Result so far: 319.0
Subtracting 180 from 194 leaves us with 14.
Include the next digit (8) from the dividend after 14, then repeat: 148 / 20

Step 5:
20 can be fit into 148 7 times, resulting in a remainder of 8.
Record the quotient 7 as the next digit in the result. 
Result so far: 3197.0
If we subtract 140 from 148, we get 8.
Include the next digit (7) from the dividend after 8, then repeat: 87 / 20

Step 6:
20 can be fit into 87 4 times, resulting in a remainder of 7.
Put 4 as the next digit of the answer. 
Result so far: 31974.0
If we take 80 away from 87, 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.

On to step 7:
70 divided by 20 is 3 with a remainder of 10.
Use 3 as the next digit of our solution. 
Result so far: 31974.3
If we take 60 away from 70, we end up 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.
Use 5 as the next digit of our solution. 
Result so far: 31974.35
The remainder is 0 after subtracting 100 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 9:
20 can be fit into 0 0 times, resulting in a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 31974.35
If we take 0 away from 0, we end up 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.

Advancing to step 10:
If we divide 0 by 20, we get 0 and a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 31974.35
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 final outcome is 31974.35, with a leftover of 0.0.