Let's divide 83941 by 21
The aim is to understand the frequency of 21 in 83941.

Advancing to step 1:
If we divide 8 by 21, we get 0 and a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 8 after subtracting 0 from 8.
Take the next digit (3) from the dividend and append it to 8, then repeat: 83 / 21

On to step 2:
If we divide 83 by 21, we get 3 and a remainder of 20.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
Subtracting 63 from 83 leaves us with 20.
Grab the next digit (9) from the dividend, add it to 20, then carry on: 209 / 21

Moving on to step 3:
If we divide 209 by 21, we get 9 and a remainder of 20.
Write down 9 as next digit of the result. 
Result so far: 39.0
The remainder is 20 after subtracting 189 from 209.
Include the next digit (4) from the dividend after 20, then repeat: 204 / 21

Going ahead to step 4:
If we divide 204 by 21, we get 9 and a remainder of 15.
Put 9 as the next digit of the answer. 
Result so far: 399.0
If we take 189 away from 204, we end up with 15.
Grab the next digit (1) from the dividend, add it to 15, then carry on: 151 / 21

Going ahead to step 5:
The number 21 fits into 151 7 times, leaving a remainder of 4.
The number 7 becomes the next digit in our result. 
Result so far: 3997.0
Subtract 147 from 151 to get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 6:
When dividing 40 by 21, we get 1 with a remainder of 19.
Write down 1 as next digit of the result. 
Result so far: 3997.1
Subtracting 21 from 40 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Step 7:
21 can be fit into 190 9 times, resulting in a remainder of 1.
Record the quotient 9 as the next digit in the result. 
Result so far: 3997.19
If we subtract 189 from 190, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 8:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 3997.19
The remainder is 10 after subtracting 0 from 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 9:
21 goes into 100 4 times with a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 3997.1904
Subtracting 84 from 100 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Step 10:
21 goes into 160 7 times with a remainder of 13.
Write down 7 as next digit of the result. 
Result so far: 3997.19047
If we take 147 away from 160, we end up with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 11:
When dividing 130 by 21, we get 6 with a remainder of 4.
Put 6 as the next digit of the answer. 
Result so far: 3997.190476
Subtract 126 from 130 to get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 12:
If we divide 40 by 21, we get 1 and a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 3997.1904761
If we subtract 21 from 40, we get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Going ahead to step 13:
If we divide 190 by 21, we get 9 and a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 3997.19047619
Deduct 189 from 190 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

In conclusion, the division gives 3997.19047619 with a balance of 1e-09.