Let's divide 338749 by 21
The aim is to understand the frequency of 21 in 338749.

Advancing to step 1:
3 divided by 21 is 0 with a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Include the next digit (3) from the dividend after 3, then repeat: 33 / 21

On to step 2:
If we divide 33 by 21, we get 1 and a remainder of 12.
The next digit of our result is 1. 
Result so far: 1.0
The remainder is 12 after subtracting 21 from 33.
Fetch the next digit (8) from the dividend, attach it to 12 and continue: 128 / 21

Step 3:
128 divided by 21 is 6 with a remainder of 2.
The number 6 becomes the next digit in our result. 
Result so far: 16.0
Subtract 126 from 128 to get 2.
Bring next digit (7) of the dividend behind the 2 and repeat the process: 27 / 21

Moving on to step 4:
21 can be fit into 27 1 times, resulting in a remainder of 6.
Use 1 as the next digit of our solution. 
Result so far: 161.0
If we take 21 away from 27, we end up with 6.
Take the next digit (4) from the dividend and append it to 6, then repeat: 64 / 21

On to step 5:
21 can be fit into 64 3 times, resulting in a remainder of 1.
Record the quotient 3 as the next digit in the result. 
Result so far: 1613.0
Subtracting 63 from 64 leaves us with 1.
Fetch the next digit (9) from the dividend, attach it to 1 and continue: 19 / 21

On to step 6:
19 divided by 21 is 0 with a remainder of 19.
Put 0 as the next digit of the answer. 
Result so far: 16130.0
Subtract 0 from 19 to 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.

Let's proceed to step 7:
The number 21 fits into 190 9 times, leaving a remainder of 1.
The next digit of our result is 9. 
Result so far: 16130.9
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.

Step 8:
If we divide 10 by 21, we get 0 and a remainder of 10.
The next digit of our result is 0. 
Result so far: 16130.9
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.

On to step 9:
The number 21 fits into 100 4 times, leaving a remainder of 16.
Write down 4 as next digit of the result. 
Result so far: 16130.904
If we subtract 84 from 100, we 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.
Put 7 as the next digit of the answer. 
Result so far: 16130.9047
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.

Moving on to step 11:
When dividing 130 by 21, we get 6 with a remainder of 4.
Record the quotient 6 as the next digit in the result. 
Result so far: 16130.90476
If we take 126 away from 130, we end up 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.

On to step 12:
21 can be fit into 40 1 times, resulting in a remainder of 19.
The next digit of our result is 1. 
Result so far: 16130.904761
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.

Going ahead to step 13:
190 divided by 21 is 9 with a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 16130.9047619
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.

Step 14:
If we divide 10 by 21, we get 0 and a remainder of 10.
The next digit of our result is 0. 
Result so far: 16130.9047619
Subtracting 0 from 10 leaves us 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.

In conclusion, the division gives 16130.9047619 with a balance of 1e-08.