We look at the division of 581812 by 20 
The aim is to understand the frequency of 20 in 581812.

Step 1:
20 can be fit into 5 0 times, resulting in a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 5, we end up with 5.
Append the next digit (8) from the dividend to 5 and continue with: 58 / 20

Going ahead to step 2:
20 goes into 58 2 times with a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Deduct 40 from 58 and we're left with 18.
Grab the next digit (1) from the dividend, add it to 18, then carry on: 181 / 20

Moving on to step 3:
The number 20 fits into 181 9 times, leaving a remainder of 1.
Record the quotient 9 as the next digit in the result. 
Result so far: 29.0
If we take 180 away from 181, we end up with 1.
Take the next digit (8) from the dividend and append it to 1, then repeat: 18 / 20

On to step 4:
When dividing 18 by 20, we get 0 with a remainder of 18.
Record the quotient 0 as the next digit in the result. 
Result so far: 290.0
Subtracting 0 from 18 leaves us with 18.
Fetch the next digit (1) from the dividend, attach it to 18 and continue: 181 / 20

On to step 5:
The number 20 fits into 181 9 times, leaving a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 2909.0
If we take 180 away from 181, we end up with 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 20

Going ahead to step 6:
The number 20 fits into 12 0 times, leaving a remainder of 12.
Record the quotient 0 as the next digit in the result. 
Result so far: 29090.0
If we take 0 away from 12, we end up with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 7:
20 can be fit into 120 6 times, resulting in a remainder of 0.
Put 6 as the next digit of the answer. 
Result so far: 29090.6
If we subtract 120 from 120, 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.

Moving on to step 8:
The number 20 fits into 0 0 times, leaving a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 29090.6
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.

Step 9:
20 goes into 0 0 times with a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 29090.6
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.

Our division results in 29090.6 with a remaining 0.0.