Let's divide 691004 by 21
The aim is to understand the frequency of 21 in 691004.

Advancing to step 1:
The number 21 fits into 6 0 times, leaving a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 6 leaves us with 6.
Fetch the next digit (9) from the dividend, attach it to 6 and continue: 69 / 21

Advancing to step 2:
If we divide 69 by 21, we get 3 and a remainder of 6.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
If we take 63 away from 69, we end up with 6.
Bring next digit (1) of the dividend behind the 6 and repeat the process: 61 / 21

Moving on to step 3:
When dividing 61 by 21, we get 2 with a remainder of 19.
Write down 2 as next digit of the result. 
Result so far: 32.0
Subtracting 42 from 61 leaves us with 19.
Take the next digit (0) from the dividend and append it to 19, then repeat: 190 / 21

Advancing to step 4:
21 goes into 190 9 times with a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 329.0
If we subtract 189 from 190, we get 1.
Bring next digit (0) of the dividend behind the 1 and repeat the process: 10 / 21

Moving on to step 5:
The number 21 fits into 10 0 times, leaving a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 3290.0
Deduct 0 from 10 and we're left with 10.
Bring next digit (4) of the dividend behind the 10 and repeat the process: 104 / 21

Let's proceed to step 6:
21 can be fit into 104 4 times, resulting in a remainder of 20.
Write down 4 as next digit of the result. 
Result so far: 32904.0
If we subtract 84 from 104, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Let's proceed to step 7:
The number 21 fits into 200 9 times, leaving a remainder of 11.
The next digit of our result is 9. 
Result so far: 32904.9
Subtracting 189 from 200 leaves us with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Step 8:
21 goes into 110 5 times with a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 32904.95
Subtract 105 from 110 to get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 9:
21 can be fit into 50 2 times, resulting in a remainder of 8.
The next digit of our result is 2. 
Result so far: 32904.952
The remainder is 8 after subtracting 42 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Moving on to step 10:
80 divided by 21 is 3 with a remainder of 17.
Put 3 as the next digit of the answer. 
Result so far: 32904.9523
Subtract 63 from 80 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Moving on to step 11:
21 can be fit into 170 8 times, resulting in a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 32904.95238
If we subtract 168 from 170, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Moving on to step 12:
21 can be fit into 20 0 times, resulting in a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 32904.95238
Deduct 0 from 20 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Let's proceed to step 13:
200 divided by 21 is 9 with a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 32904.9523809
Deduct 189 from 200 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 14:
The number 21 fits into 110 5 times, leaving a remainder of 5.
The next digit of our result is 5. 
Result so far: 32904.95238095
The remainder is 5 after subtracting 105 from 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

After the division, we end up with 32904.95238095 and a remainder of 5e-09.