297828 ÷ 21 
The aim is to understand the frequency of 21 in 297828.

Advancing to step 1:
If we divide 2 by 21, we get 0 and a remainder of 2.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 2, we end up with 2.
Grab the next digit (9) from the dividend, add it to 2, then carry on: 29 / 21

Going ahead to step 2:
29 divided by 21 is 1 with a remainder of 8.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtract 21 from 29 to get 8.
Append the next digit (7) from the dividend to 8 and continue with: 87 / 21

Advancing to step 3:
87 divided by 21 is 4 with a remainder of 3.
Write down 4 as next digit of the result. 
Result so far: 14.0
If we take 84 away from 87, we end up with 3.
Append the next digit (8) from the dividend to 3 and continue with: 38 / 21

Advancing to step 4:
21 goes into 38 1 times with a remainder of 17.
The next digit of our result is 1. 
Result so far: 141.0
Subtracting 21 from 38 leaves us with 17.
Include the next digit (2) from the dividend after 17, then repeat: 172 / 21

On to step 5:
When dividing 172 by 21, we get 8 with a remainder of 4.
The number 8 becomes the next digit in our result. 
Result so far: 1418.0
If we take 168 away from 172, we end up with 4.
Include the next digit (8) from the dividend after 4, then repeat: 48 / 21

Step 6:
If we divide 48 by 21, we get 2 and a remainder of 6.
The next digit of our result is 2. 
Result so far: 14182.0
Deduct 42 from 48 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 7:
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: 14182.2
The remainder is 18 after subtracting 42 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Step 8:
180 divided by 21 is 8 with a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 14182.28
Subtracting 168 from 180 leaves us 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.

Let's proceed to step 9:
The number 21 fits into 120 5 times, leaving a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 14182.285
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 10:
If we divide 150 by 21, we get 7 and a remainder of 3.
The next digit of our result is 7. 
Result so far: 14182.2857
The remainder is 3 after subtracting 147 from 150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Advancing to step 11:
21 goes into 30 1 times with a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 14182.28571
If we take 21 away from 30, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Let's proceed to step 12:
90 divided by 21 is 4 with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 14182.285714
If we subtract 84 from 90, we 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.

Let's proceed to step 13:
60 divided by 21 is 2 with a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 14182.2857142
Deduct 42 from 60 and we're left 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 14:
If we divide 180 by 21, we get 8 and a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 14182.28571428
Subtract 168 from 180 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.

In conclusion, the division gives 14182.28571428 with a balance of 1.2e-08.