We're dividing 65884 by 21 
The aim is to understand the frequency of 21 in 65884.

On to step 1:
The number 21 fits into 6 0 times, leaving a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Take the next digit (5) from the dividend and append it to 6, then repeat: 65 / 21

Going ahead to step 2:
65 divided by 21 is 3 with a remainder of 2.
Use 3 as the next digit of our solution. 
Result so far: 3.0
The remainder is 2 after subtracting 63 from 65.
Include the next digit (8) from the dividend after 2, then repeat: 28 / 21

Moving on to step 3:
If we divide 28 by 21, we get 1 and a remainder of 7.
Write down 1 as next digit of the result. 
Result so far: 31.0
Subtracting 21 from 28 leaves us with 7.
Bring next digit (8) of the dividend behind the 7 and repeat the process: 78 / 21

On to step 4:
The number 21 fits into 78 3 times, leaving a remainder of 15.
Record the quotient 3 as the next digit in the result. 
Result so far: 313.0
If we take 63 away from 78, we end up with 15.
Bring next digit (4) of the dividend behind the 15 and repeat the process: 154 / 21

Step 5:
154 divided by 21 is 7 with a remainder of 7.
Record the quotient 7 as the next digit in the result. 
Result so far: 3137.0
The remainder is 7 after subtracting 147 from 154.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Step 6:
21 goes into 70 3 times with a remainder of 7.
Put 3 as the next digit of the answer. 
Result so far: 3137.3
If we subtract 63 from 70, we get 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 7:
70 divided by 21 is 3 with a remainder of 7.
Put 3 as the next digit of the answer. 
Result so far: 3137.33
Subtracting 63 from 70 leaves us 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.

After the division, we end up with 3137.33 and a remainder of 0.007.