Let's divide 438184 by 21
The aim is to understand the frequency of 21 in 438184.

On to step 1:
When dividing 4 by 21, we get 0 with a remainder of 4.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 4 leaves us with 4.
Fetch the next digit (3) from the dividend, attach it to 4 and continue: 43 / 21

Going ahead to step 2:
21 goes into 43 2 times with a remainder of 1.
The next digit of our result is 2. 
Result so far: 2.0
The remainder is 1 after subtracting 42 from 43.
Fetch the next digit (8) from the dividend, attach it to 1 and continue: 18 / 21

On to step 3:
When dividing 18 by 21, we get 0 with a remainder of 18.
The next digit of our result is 0. 
Result so far: 20.0
Subtract 0 from 18 to get 18.
Grab the next digit (1) from the dividend, add it to 18, then carry on: 181 / 21

Moving on to step 4:
21 goes into 181 8 times with a remainder of 13.
Use 8 as the next digit of our solution. 
Result so far: 208.0
Deduct 168 from 181 and we're left with 13.
Fetch the next digit (8) from the dividend, attach it to 13 and continue: 138 / 21

Step 5:
21 goes into 138 6 times with a remainder of 12.
Put 6 as the next digit of the answer. 
Result so far: 2086.0
If we subtract 126 from 138, we get 12.
Take the next digit (4) from the dividend and append it to 12, then repeat: 124 / 21

Step 6:
When dividing 124 by 21, we get 5 with a remainder of 19.
Record the quotient 5 as the next digit in the result. 
Result so far: 20865.0
If we take 105 away from 124, we end up 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:
The number 21 fits into 190 9 times, leaving a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 20865.9
The remainder is 1 after subtracting 189 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 8:
If we divide 10 by 21, we get 0 and a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 20865.9
Deduct 0 from 10 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 9:
21 goes into 100 4 times with a remainder of 16.
Write down 4 as next digit of the result. 
Result so far: 20865.904
Subtract 84 from 100 to get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Moving on to step 10:
160 divided by 21 is 7 with a remainder of 13.
Write down 7 as next digit of the result. 
Result so far: 20865.9047
Subtracting 147 from 160 leaves us 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.

Let's proceed to step 11:
130 divided by 21 is 6 with a remainder of 4.
Record the quotient 6 as the next digit in the result. 
Result so far: 20865.90476
Subtracting 126 from 130 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 12:
The number 21 fits into 40 1 times, leaving a remainder of 19.
The next digit of our result is 1. 
Result so far: 20865.904761
The remainder is 19 after subtracting 21 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Step 13:
190 divided by 21 is 9 with a remainder of 1.
The next digit of our result is 9. 
Result so far: 20865.9047619
Subtract 189 from 190 to 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.

Going ahead to step 14:
21 goes into 10 0 times with a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 20865.9047619
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.

The final outcome is 20865.9047619, with a leftover of 1e-08.