We divide 173511 by 21
The aim is to understand the frequency of 21 in 173511.

Step 1:
21 goes into 1 0 times with a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 1, we get 1.
Include the next digit (7) from the dividend after 1, then repeat: 17 / 21

Going ahead to step 2:
21 goes into 17 0 times with a remainder of 17.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 17 to get 17.
Bring next digit (3) of the dividend behind the 17 and repeat the process: 173 / 21

Let's proceed to step 3:
If we divide 173 by 21, we get 8 and a remainder of 5.
The number 8 becomes the next digit in our result. 
Result so far: 8.0
The remainder is 5 after subtracting 168 from 173.
Take the next digit (5) from the dividend and append it to 5, then repeat: 55 / 21

On to step 4:
If we divide 55 by 21, we get 2 and a remainder of 13.
Record the quotient 2 as the next digit in the result. 
Result so far: 82.0
Subtracting 42 from 55 leaves us with 13.
Fetch the next digit (1) from the dividend, attach it to 13 and continue: 131 / 21

Going ahead to step 5:
21 goes into 131 6 times with a remainder of 5.
Use 6 as the next digit of our solution. 
Result so far: 826.0
Subtract 126 from 131 to get 5.
Take the next digit (1) from the dividend and append it to 5, then repeat: 51 / 21

Advancing to step 6:
21 can be fit into 51 2 times, resulting in a remainder of 9.
Record the quotient 2 as the next digit in the result. 
Result so far: 8262.0
If we take 42 away from 51, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Let's proceed to step 7:
21 goes into 90 4 times with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 8262.4
Deduct 84 from 90 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 8:
When dividing 60 by 21, we get 2 with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 8262.42
The remainder is 18 after subtracting 42 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

On to step 9:
180 divided by 21 is 8 with a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 8262.428
Deduct 168 from 180 and we're left with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Let's proceed to step 10:
When dividing 120 by 21, we get 5 with a remainder of 15.
The next digit of our result is 5. 
Result so far: 8262.4285
Subtract 105 from 120 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 11:
If we divide 150 by 21, we get 7 and a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 8262.42857
Deduct 147 from 150 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Moving on to step 12:
When dividing 30 by 21, we get 1 with a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 8262.428571
If we take 21 away from 30, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Step 13:
90 divided by 21 is 4 with a remainder of 6.
The next digit of our result is 4. 
Result so far: 8262.4285714
The remainder is 6 after subtracting 84 from 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

On to step 14:
60 divided by 21 is 2 with a remainder of 18.
Record the quotient 2 as the next digit in the result. 
Result so far: 8262.42857142
Deduct 42 from 60 and we're left with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

The quotient of the division is 8262.42857142, and the remainder is 1.8e-08.