We divide 874909 by 21
The aim is to understand the frequency of 21 in 874909.

Going ahead to step 1:
The number 21 fits into 8 0 times, leaving a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Grab the next digit (7) from the dividend, add it to 8, then carry on: 87 / 21

Step 2:
If we divide 87 by 21, we get 4 and a remainder of 3.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
The remainder is 3 after subtracting 84 from 87.
Bring next digit (4) of the dividend behind the 3 and repeat the process: 34 / 21

On to step 3:
34 divided by 21 is 1 with a remainder of 13.
The next digit of our result is 1. 
Result so far: 41.0
The remainder is 13 after subtracting 21 from 34.
Append the next digit (9) from the dividend to 13 and continue with: 139 / 21

Going ahead to step 4:
When dividing 139 by 21, we get 6 with a remainder of 13.
Use 6 as the next digit of our solution. 
Result so far: 416.0
If we take 126 away from 139, we end up with 13.
Fetch the next digit (0) from the dividend, attach it to 13 and continue: 130 / 21

Let's proceed to step 5:
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: 4166.0
The remainder is 4 after subtracting 126 from 130.
Fetch the next digit (9) from the dividend, attach it to 4 and continue: 49 / 21

Advancing to step 6:
49 divided by 21 is 2 with a remainder of 7.
The number 2 becomes the next digit in our result. 
Result so far: 41662.0
Subtract 42 from 49 to get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Let's proceed to step 7:
If we divide 70 by 21, we get 3 and a remainder of 7.
Write down 3 as next digit of the result. 
Result so far: 41662.3
Deduct 63 from 70 and we're left with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Going ahead to step 8:
The number 21 fits into 70 3 times, leaving a remainder of 7.
Use 3 as the next digit of our solution. 
Result so far: 41662.33
Subtracting 63 from 70 leaves us with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

In conclusion, the division gives 41662.33 with a balance of 0.007.