We divide 966551 by 21
The aim is to understand the frequency of 21 in 966551.

On to step 1:
9 divided by 21 is 0 with a remainder of 9.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 9 to get 9.
Take the next digit (6) from the dividend and append it to 9, then repeat: 96 / 21

Let's proceed to step 2:
21 can be fit into 96 4 times, resulting in a remainder of 12.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
If we take 84 away from 96, we end up with 12.
Grab the next digit (6) from the dividend, add it to 12, then carry on: 126 / 21

Advancing to step 3:
126 divided by 21 is 6 with a remainder of 0.
Record the quotient 6 as the next digit in the result. 
Result so far: 46.0
Deduct 126 from 126 and we're left with 0.
Bring next digit (5) of the dividend behind the 0 and repeat the process: 5 / 21

On to step 4:
The number 21 fits into 5 0 times, leaving a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 460.0
Deduct 0 from 5 and we're left with 5.
Append the next digit (5) from the dividend to 5 and continue with: 55 / 21

Moving on to step 5:
When dividing 55 by 21, we get 2 with a remainder of 13.
The next digit of our result is 2. 
Result so far: 4602.0
If we subtract 42 from 55, we get 13.
Grab the next digit (1) from the dividend, add it to 13, then carry on: 131 / 21

Moving on to step 6:
The number 21 fits into 131 6 times, leaving a remainder of 5.
The number 6 becomes the next digit in our result. 
Result so far: 46026.0
Deduct 126 from 131 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Moving on to step 7:
The number 21 fits into 50 2 times, leaving a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 46026.2
If we subtract 42 from 50, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Advancing to step 8:
80 divided by 21 is 3 with a remainder of 17.
Put 3 as the next digit of the answer. 
Result so far: 46026.23
Deduct 63 from 80 and we're left with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Step 9:
If we divide 170 by 21, we get 8 and a remainder of 2.
Use 8 as the next digit of our solution. 
Result so far: 46026.238
Subtracting 168 from 170 leaves us with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

On to step 10:
21 goes into 20 0 times with a remainder of 20.
Put 0 as the next digit of the answer. 
Result so far: 46026.238
If we subtract 0 from 20, 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 11:
21 goes into 200 9 times with a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 46026.23809
If we take 189 away from 200, we end up 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 12:
The number 21 fits into 110 5 times, leaving a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 46026.238095
If we subtract 105 from 110, we 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.

Moving on to step 13:
If we divide 50 by 21, we get 2 and a remainder of 8.
The next digit of our result is 2. 
Result so far: 46026.2380952
Subtracting 42 from 50 leaves us with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 14:
21 goes into 80 3 times with a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 46026.23809523
Deduct 63 from 80 and we're left with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

In conclusion, the division gives 46026.23809523 with a balance of 1.7e-08.