We divide 998352 by 21
The aim is to understand the frequency of 21 in 998352.

Going ahead to step 1:
21 can be fit into 9 0 times, resulting in a remainder of 9.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 9 leaves us with 9.
Include the next digit (9) from the dividend after 9, then repeat: 99 / 21

Step 2:
If we divide 99 by 21, we get 4 and a remainder of 15.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
Deduct 84 from 99 and we're left with 15.
Append the next digit (8) from the dividend to 15 and continue with: 158 / 21

Let's proceed to step 3:
21 can be fit into 158 7 times, resulting in a remainder of 11.
The number 7 becomes the next digit in our result. 
Result so far: 47.0
Subtracting 147 from 158 leaves us with 11.
Bring next digit (3) of the dividend behind the 11 and repeat the process: 113 / 21

Let's proceed to step 4:
21 goes into 113 5 times with a remainder of 8.
Use 5 as the next digit of our solution. 
Result so far: 475.0
If we take 105 away from 113, we end up with 8.
Fetch the next digit (5) from the dividend, attach it to 8 and continue: 85 / 21

Step 5:
21 can be fit into 85 4 times, resulting in a remainder of 1.
The next digit of our result is 4. 
Result so far: 4754.0
The remainder is 1 after subtracting 84 from 85.
Include the next digit (2) from the dividend after 1, then repeat: 12 / 21

Moving on to step 6:
The number 21 fits into 12 0 times, leaving a remainder of 12.
The next digit of our result is 0. 
Result so far: 47540.0
Subtract 0 from 12 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 7:
120 divided by 21 is 5 with a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 47540.5
Deduct 105 from 120 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 8:
21 goes into 150 7 times with a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 47540.57
Deduct 147 from 150 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 9:
The number 21 fits into 30 1 times, leaving a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 47540.571
If we subtract 21 from 30, we get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Moving on to step 10:
If we divide 90 by 21, we get 4 and a remainder of 6.
The next digit of our result is 4. 
Result so far: 47540.5714
Subtract 84 from 90 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 11:
When dividing 60 by 21, we get 2 with a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 47540.57142
If we take 42 away from 60, we end up 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.

Advancing to step 12:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 47540.571428
Deduct 168 from 180 and we're left 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.

Step 13:
120 divided by 21 is 5 with a remainder of 15.
The next digit of our result is 5. 
Result so far: 47540.5714285
The remainder is 15 after subtracting 105 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 14:
If we divide 150 by 21, we get 7 and a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 47540.57142857
Subtract 147 from 150 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Our division results in 47540.57142857 with a remaining 3e-09.