We look at the division of 521839 by 20 
The aim is to understand the frequency of 20 in 521839.

Advancing to step 1:
The number 20 fits into 5 0 times, leaving a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 5 and we're left with 5.
Bring next digit (2) of the dividend behind the 5 and repeat the process: 52 / 20

Step 2:
The number 20 fits into 52 2 times, leaving a remainder of 12.
Write down 2 as next digit of the result. 
Result so far: 2.0
Subtract 40 from 52 to get 12.
Take the next digit (1) from the dividend and append it to 12, then repeat: 121 / 20

Moving on to step 3:
20 can be fit into 121 6 times, resulting in a remainder of 1.
The next digit of our result is 6. 
Result so far: 26.0
If we subtract 120 from 121, we get 1.
Fetch the next digit (8) from the dividend, attach it to 1 and continue: 18 / 20

On to step 4:
If we divide 18 by 20, we get 0 and a remainder of 18.
The next digit of our result is 0. 
Result so far: 260.0
If we subtract 0 from 18, we get 18.
Append the next digit (3) from the dividend to 18 and continue with: 183 / 20

Step 5:
The number 20 fits into 183 9 times, leaving a remainder of 3.
Write down 9 as next digit of the result. 
Result so far: 2609.0
Subtract 180 from 183 to get 3.
Grab the next digit (9) from the dividend, add it to 3, then carry on: 39 / 20

Moving on to step 6:
If we divide 39 by 20, we get 1 and a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 26091.0
If we subtract 20 from 39, 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:
190 divided by 20 is 9 with a remainder of 10.
Record the quotient 9 as the next digit in the result. 
Result so far: 26091.9
The remainder is 10 after subtracting 180 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 8:
20 goes into 100 5 times with a remainder of 0.
The next digit of our result is 5. 
Result so far: 26091.95
Deduct 100 from 100 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.

On to step 9:
When dividing 0 by 20, we get 0 with a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 26091.95
Subtract 0 from 0 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.

Advancing to step 10:
If we divide 0 by 20, we get 0 and a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 26091.95
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.

After the division, we end up with 26091.95 and a remainder of 0.0.