We look at the division of 51093518 by 20 
The aim is to understand the frequency of 20 in 51093518.

On to step 1:
The number 20 fits into 5 0 times, leaving a remainder of 5.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 5, we get 5.
Take the next digit (1) from the dividend and append it to 5, then repeat: 51 / 20

Let's proceed to step 2:
If we divide 51 by 20, we get 2 and a remainder of 11.
Put 2 as the next digit of the answer. 
Result so far: 2.0
Subtracting 40 from 51 leaves us with 11.
Take the next digit (0) from the dividend and append it to 11, then repeat: 110 / 20

Moving on to step 3:
The number 20 fits into 110 5 times, leaving a remainder of 10.
The number 5 becomes the next digit in our result. 
Result so far: 25.0
Subtract 100 from 110 to get 10.
Fetch the next digit (9) from the dividend, attach it to 10 and continue: 109 / 20

Step 4:
109 divided by 20 is 5 with a remainder of 9.
The next digit of our result is 5. 
Result so far: 255.0
If we subtract 100 from 109, we get 9.
Fetch the next digit (3) from the dividend, attach it to 9 and continue: 93 / 20

Going ahead to step 5:
93 divided by 20 is 4 with a remainder of 13.
Use 4 as the next digit of our solution. 
Result so far: 2554.0
If we subtract 80 from 93, we get 13.
Include the next digit (5) from the dividend after 13, then repeat: 135 / 20

Moving on to step 6:
20 goes into 135 6 times with a remainder of 15.
Put 6 as the next digit of the answer. 
Result so far: 25546.0
If we subtract 120 from 135, we get 15.
Fetch the next digit (1) from the dividend, attach it to 15 and continue: 151 / 20

Let's proceed to step 7:
20 can be fit into 151 7 times, resulting in a remainder of 11.
Record the quotient 7 as the next digit in the result. 
Result so far: 255467.0
If we subtract 140 from 151, we get 11.
Bring next digit (8) of the dividend behind the 11 and repeat the process: 118 / 20

Moving on to step 8:
118 divided by 20 is 5 with a remainder of 18.
Record the quotient 5 as the next digit in the result. 
Result so far: 2554675.0
Subtracting 100 from 118 leaves us with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Step 9:
If we divide 180 by 20, we get 9 and a remainder of 0.
Put 9 as the next digit of the answer. 
Result so far: 2554675.9
If we take 180 away from 180, 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.

Going ahead to step 10:
The number 20 fits into 0 0 times, leaving a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 2554675.9
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.

On to step 11:
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: 2554675.9
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.

The final result is 2554675.9 with a remainder of 0.0.