We divide 567423 by 21
The aim is to understand the frequency of 21 in 567423.

Going ahead to step 1:
5 divided by 21 is 0 with a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 5 after subtracting 0 from 5.
Append the next digit (6) from the dividend to 5 and continue with: 56 / 21

Let's proceed to step 2:
The number 21 fits into 56 2 times, leaving a remainder of 14.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Subtracting 42 from 56 leaves us with 14.
Fetch the next digit (7) from the dividend, attach it to 14 and continue: 147 / 21

Moving on to step 3:
When dividing 147 by 21, we get 7 with a remainder of 0.
Record the quotient 7 as the next digit in the result. 
Result so far: 27.0
Subtracting 147 from 147 leaves us with 0.
Bring next digit (4) of the dividend behind the 0 and repeat the process: 4 / 21

Step 4:
When dividing 4 by 21, we get 0 with a remainder of 4.
Use 0 as the next digit of our solution. 
Result so far: 270.0
Subtract 0 from 4 to get 4.
Bring next digit (2) of the dividend behind the 4 and repeat the process: 42 / 21

Moving on to step 5:
21 can be fit into 42 2 times, resulting in a remainder of 0.
The number 2 becomes the next digit in our result. 
Result so far: 2702.0
Subtract 42 from 42 to get 0.
Grab the next digit (3) from the dividend, add it to 0, then carry on: 3 / 21

Moving on to step 6:
When dividing 3 by 21, we get 0 with a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 27020.0
The remainder is 3 after subtracting 0 from 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

On to step 7:
When dividing 30 by 21, we get 1 with a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 27020.1
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.

Advancing to step 8:
90 divided by 21 is 4 with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 27020.14
Subtracting 84 from 90 leaves us 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.

Let's proceed to step 9:
21 can be fit into 60 2 times, resulting in a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 27020.142
Subtracting 42 from 60 leaves us 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.

Let's proceed to step 10:
When dividing 180 by 21, we get 8 with a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 27020.1428
If we subtract 168 from 180, we get 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 11:
21 goes into 120 5 times with a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 27020.14285
The remainder is 15 after subtracting 105 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 12:
150 divided by 21 is 7 with a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 27020.142857
Subtracting 147 from 150 leaves us 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.

Advancing to step 13:
The number 21 fits into 30 1 times, leaving a remainder of 9.
The next digit of our result is 1. 
Result so far: 27020.1428571
Subtract 21 from 30 to get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

On to step 14:
21 goes into 90 4 times with a remainder of 6.
The number 4 becomes the next digit in our result. 
Result so far: 27020.14285714
Subtract 84 from 90 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Our division results in 27020.14285714 with a remaining 6e-09.