21216001 divided by 998 
The aim is to understand the frequency of 998 in 21216001.

On to step 1:
If we divide 2 by 998, we get 0 and a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 998

Advancing to step 2:
998 can be fit into 21 0 times, resulting in a remainder of 21.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 21, we get 21.
Fetch the next digit (2) from the dividend, attach it to 21 and continue: 212 / 998

On to step 3:
998 goes into 212 0 times with a remainder of 212.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 212, we end up with 212.
Fetch the next digit (1) from the dividend, attach it to 212 and continue: 2121 / 998

Moving on to step 4:
If we divide 2121 by 998, we get 2 and a remainder of 125.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Subtract 1996 from 2121 to get 125.
Grab the next digit (6) from the dividend, add it to 125, then carry on: 1256 / 998

Going ahead to step 5:
The number 998 fits into 1256 1 times, leaving a remainder of 258.
The number 1 becomes the next digit in our result. 
Result so far: 21.0
Subtracting 998 from 1256 leaves us with 258.
Bring next digit (0) of the dividend behind the 258 and repeat the process: 2580 / 998

Moving on to step 6:
The number 998 fits into 2580 2 times, leaving a remainder of 584.
Put 2 as the next digit of the answer. 
Result so far: 212.0
If we take 1996 away from 2580, we end up with 584.
Append the next digit (0) from the dividend to 584 and continue with: 5840 / 998

Moving on to step 7:
The number 998 fits into 5840 5 times, leaving a remainder of 850.
Use 5 as the next digit of our solution. 
Result so far: 2125.0
Deduct 4990 from 5840 and we're left with 850.
Grab the next digit (1) from the dividend, add it to 850, then carry on: 8501 / 998

Advancing to step 8:
When dividing 8501 by 998, we get 8 with a remainder of 517.
The number 8 becomes the next digit in our result. 
Result so far: 21258.0
If we subtract 7984 from 8501, we get 517.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5170, and continue the process.

Going ahead to step 9:
If we divide 5170 by 998, we get 5 and a remainder of 180.
The number 5 becomes the next digit in our result. 
Result so far: 21258.5
If we take 4990 away from 5170, we end up with 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1800, and continue the process.

Let's proceed to step 10:
998 goes into 1800 1 times with a remainder of 802.
Write down 1 as next digit of the result. 
Result so far: 21258.51
The remainder is 802 after subtracting 998 from 1800.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8020, and continue the process.

On to step 11:
998 goes into 8020 8 times with a remainder of 36.
Put 8 as the next digit of the answer. 
Result so far: 21258.518
Deduct 7984 from 8020 and we're left with 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Going ahead to step 12:
The number 998 fits into 360 0 times, leaving a remainder of 360.
Write down 0 as next digit of the result. 
Result so far: 21258.518
Deduct 0 from 360 and we're left with 360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3600, and continue the process.

Let's proceed to step 13:
If we divide 3600 by 998, we get 3 and a remainder of 606.
Record the quotient 3 as the next digit in the result. 
Result so far: 21258.51803
Subtracting 2994 from 3600 leaves us with 606.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6060, and continue the process.

Step 14:
The number 998 fits into 6060 6 times, leaving a remainder of 72.
Put 6 as the next digit of the answer. 
Result so far: 21258.518036
Subtract 5988 from 6060 to get 72.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

Going ahead to step 15:
720 divided by 998 is 0 with a remainder of 720.
Record the quotient 0 as the next digit in the result. 
Result so far: 21258.518036
Subtract 0 from 720 to get 720.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7200, and continue the process.

Going ahead to step 16:
7200 divided by 998 is 7 with a remainder of 214.
The next digit of our result is 7. 
Result so far: 21258.51803607
Subtracting 6986 from 7200 leaves us with 214.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2140, and continue the process.

In conclusion, the division gives 21258.51803607 with a balance of 2.14e-07.