Let's divide 49972804 by 21
The aim is to understand the frequency of 21 in 49972804.

On to step 1:
21 goes into 4 0 times with a remainder of 4.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Take the next digit (9) from the dividend and append it to 4, then repeat: 49 / 21

Moving on to step 2:
21 can be fit into 49 2 times, resulting in a remainder of 7.
Use 2 as the next digit of our solution. 
Result so far: 2.0
The remainder is 7 after subtracting 42 from 49.
Take the next digit (9) from the dividend and append it to 7, then repeat: 79 / 21

Step 3:
If we divide 79 by 21, we get 3 and a remainder of 16.
The number 3 becomes the next digit in our result. 
Result so far: 23.0
If we take 63 away from 79, we end up with 16.
Include the next digit (7) from the dividend after 16, then repeat: 167 / 21

Advancing to step 4:
When dividing 167 by 21, we get 7 with a remainder of 20.
Use 7 as the next digit of our solution. 
Result so far: 237.0
Subtracting 147 from 167 leaves us with 20.
Grab the next digit (2) from the dividend, add it to 20, then carry on: 202 / 21

Going ahead to step 5:
21 can be fit into 202 9 times, resulting in a remainder of 13.
The number 9 becomes the next digit in our result. 
Result so far: 2379.0
The remainder is 13 after subtracting 189 from 202.
Take the next digit (8) from the dividend and append it to 13, then repeat: 138 / 21

Going ahead to step 6:
When dividing 138 by 21, we get 6 with a remainder of 12.
The next digit of our result is 6. 
Result so far: 23796.0
If we subtract 126 from 138, we get 12.
Bring next digit (0) of the dividend behind the 12 and repeat the process: 120 / 21

Going ahead to step 7:
21 goes into 120 5 times with a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 237965.0
Subtracting 105 from 120 leaves us with 15.
Fetch the next digit (4) from the dividend, attach it to 15 and continue: 154 / 21

Moving on to step 8:
21 can be fit into 154 7 times, resulting in a remainder of 7.
Use 7 as the next digit of our solution. 
Result so far: 2379657.0
Deduct 147 from 154 and we're left 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.

Advancing to step 9:
The number 21 fits into 70 3 times, leaving a remainder of 7.
Use 3 as the next digit of our solution. 
Result so far: 2379657.3
Deduct 63 from 70 and we're left 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.

Moving on to step 10:
If we divide 70 by 21, we get 3 and a remainder of 7.
The next digit of our result is 3. 
Result so far: 2379657.33
Deduct 63 from 70 and we're left 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.

Our division results in 2379657.33 with a remaining 0.007.