We look at the division of 267424 by 21 
The aim is to understand the frequency of 21 in 267424.

Let's proceed to step 1:
21 goes into 2 0 times with a remainder of 2.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 2, we end up with 2.
Append the next digit (6) from the dividend to 2 and continue with: 26 / 21

Let's proceed to step 2:
26 divided by 21 is 1 with a remainder of 5.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Subtract 21 from 26 to get 5.
Append the next digit (7) from the dividend to 5 and continue with: 57 / 21

On to step 3:
If we divide 57 by 21, we get 2 and a remainder of 15.
The number 2 becomes the next digit in our result. 
Result so far: 12.0
Subtract 42 from 57 to get 15.
Include the next digit (4) from the dividend after 15, then repeat: 154 / 21

Advancing to step 4:
When dividing 154 by 21, we get 7 with a remainder of 7.
Put 7 as the next digit of the answer. 
Result so far: 127.0
Subtracting 147 from 154 leaves us with 7.
Grab the next digit (2) from the dividend, add it to 7, then carry on: 72 / 21

Let's proceed to step 5:
If we divide 72 by 21, we get 3 and a remainder of 9.
Write down 3 as next digit of the result. 
Result so far: 1273.0
If we take 63 away from 72, we end up with 9.
Fetch the next digit (4) from the dividend, attach it to 9 and continue: 94 / 21

Going ahead to step 6:
21 can be fit into 94 4 times, resulting in a remainder of 10.
The next digit of our result is 4. 
Result so far: 12734.0
The remainder is 10 after subtracting 84 from 94.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 7:
The number 21 fits into 100 4 times, leaving a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 12734.4
If we take 84 away from 100, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Let's proceed to step 8:
The number 21 fits into 160 7 times, leaving a remainder of 13.
Record the quotient 7 as the next digit in the result. 
Result so far: 12734.47
Subtracting 147 from 160 leaves us with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Let's proceed to step 9:
If we divide 130 by 21, we get 6 and a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 12734.476
Subtracting 126 from 130 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 10:
The number 21 fits into 40 1 times, leaving a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 12734.4761
If we take 21 away from 40, we end up with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Let's proceed to step 11:
If we divide 190 by 21, we get 9 and a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 12734.47619
If we subtract 189 from 190, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 12:
When dividing 10 by 21, we get 0 with a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 12734.47619
Deduct 0 from 10 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 13:
21 goes into 100 4 times with a remainder of 16.
The next digit of our result is 4. 
Result so far: 12734.4761904
The remainder is 16 after subtracting 84 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Advancing to step 14:
160 divided by 21 is 7 with a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 12734.47619047
The remainder is 13 after subtracting 147 from 160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

The final outcome is 12734.47619047, with a leftover of 1.3e-08.