608601 ÷ 21 
The aim is to understand the frequency of 21 in 608601.

On to step 1:
21 can be fit into 6 0 times, resulting in a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Include the next digit (0) from the dividend after 6, then repeat: 60 / 21

Let's proceed to step 2:
If we divide 60 by 21, we get 2 and a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Subtracting 42 from 60 leaves us with 18.
Fetch the next digit (8) from the dividend, attach it to 18 and continue: 188 / 21

Advancing to step 3:
21 goes into 188 8 times with a remainder of 20.
The next digit of our result is 8. 
Result so far: 28.0
Deduct 168 from 188 and we're left with 20.
Fetch the next digit (6) from the dividend, attach it to 20 and continue: 206 / 21

Advancing to step 4:
When dividing 206 by 21, we get 9 with a remainder of 17.
Write down 9 as next digit of the result. 
Result so far: 289.0
If we take 189 away from 206, we end up with 17.
Take the next digit (0) from the dividend and append it to 17, then repeat: 170 / 21

Going ahead to step 5:
21 can be fit into 170 8 times, resulting in a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 2898.0
Deduct 168 from 170 and we're left with 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 21

Advancing to step 6:
The number 21 fits into 21 1 times, leaving a remainder of 0.
The number 1 becomes the next digit in our result. 
Result so far: 28981.0
The remainder is 0 after subtracting 21 from 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 7:
If we divide 0 by 21, we get 0 and a remainder of 0.
The next digit of our result is 0. 
Result so far: 28981.0
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 8:
If we divide 0 by 21, we get 0 and a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 28981.0
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The quotient of the division is 28981.0, and the remainder is 0.0.