813539 ÷ 20 
The aim is to understand the frequency of 20 in 813539.

Let's proceed to step 1:
8 divided by 20 is 0 with a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Append the next digit (1) from the dividend to 8 and continue with: 81 / 20

Moving on to step 2:
If we divide 81 by 20, we get 4 and a remainder of 1.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
If we take 80 away from 81, we end up with 1.
Append the next digit (3) from the dividend to 1 and continue with: 13 / 20

Advancing to step 3:
If we divide 13 by 20, we get 0 and a remainder of 13.
Write down 0 as next digit of the result. 
Result so far: 40.0
If we take 0 away from 13, we end up with 13.
Take the next digit (5) from the dividend and append it to 13, then repeat: 135 / 20

Advancing to step 4:
When dividing 135 by 20, we get 6 with a remainder of 15.
The next digit of our result is 6. 
Result so far: 406.0
If we subtract 120 from 135, we get 15.
Take the next digit (3) from the dividend and append it to 15, then repeat: 153 / 20

Going ahead to step 5:
20 goes into 153 7 times with a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 4067.0
Subtracting 140 from 153 leaves us with 13.
Include the next digit (9) from the dividend after 13, then repeat: 139 / 20

Let's proceed to step 6:
139 divided by 20 is 6 with a remainder of 19.
The number 6 becomes the next digit in our result. 
Result so far: 40676.0
If we subtract 120 from 139, we get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Moving on to step 7:
When dividing 190 by 20, we get 9 with a remainder of 10.
Record the quotient 9 as the next digit in the result. 
Result so far: 40676.9
Subtract 180 from 190 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 8:
20 goes into 100 5 times with a remainder of 0.
Use 5 as the next digit of our solution. 
Result so far: 40676.95
Subtracting 100 from 100 leaves us 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.

Moving on to step 9:
If we divide 0 by 20, we get 0 and a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 40676.95
If we subtract 0 from 0, we 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.

Advancing to step 10:
0 divided by 20 is 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 40676.95
Subtracting 0 from 0 leaves us 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.

Our division results in 40676.95 with a remaining 0.0.