325983 ÷ 21 
The aim is to understand the frequency of 21 in 325983.

Let's proceed to step 1:
3 divided by 21 is 0 with a remainder of 3.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Grab the next digit (2) from the dividend, add it to 3, then carry on: 32 / 21

Let's proceed to step 2:
21 goes into 32 1 times with a remainder of 11.
Use 1 as the next digit of our solution. 
Result so far: 1.0
The remainder is 11 after subtracting 21 from 32.
Take the next digit (5) from the dividend and append it to 11, then repeat: 115 / 21

Moving on to step 3:
If we divide 115 by 21, we get 5 and a remainder of 10.
The next digit of our result is 5. 
Result so far: 15.0
The remainder is 10 after subtracting 105 from 115.
Append the next digit (9) from the dividend to 10 and continue with: 109 / 21

Let's proceed to step 4:
109 divided by 21 is 5 with a remainder of 4.
Put 5 as the next digit of the answer. 
Result so far: 155.0
If we subtract 105 from 109, we get 4.
Append the next digit (8) from the dividend to 4 and continue with: 48 / 21

Let's proceed to step 5:
If we divide 48 by 21, we get 2 and a remainder of 6.
Write down 2 as next digit of the result. 
Result so far: 1552.0
Deduct 42 from 48 and we're left with 6.
Bring next digit (3) of the dividend behind the 6 and repeat the process: 63 / 21

Moving on to step 6:
21 goes into 63 3 times with a remainder of 0.
Put 3 as the next digit of the answer. 
Result so far: 15523.0
The remainder is 0 after subtracting 63 from 63.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 7:
0 divided by 21 is 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 15523.0
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.

Advancing to step 8:
0 divided by 21 is 0 with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 15523.0
Subtract 0 from 0 to 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.

Our division results in 15523.0 with a remaining 0.0.