Let's divide 287274 by 21
The aim is to understand the frequency of 21 in 287274.

Moving on to step 1:
When dividing 2 by 21, we get 0 with a remainder of 2.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Append the next digit (8) from the dividend to 2 and continue with: 28 / 21

Step 2:
When dividing 28 by 21, we get 1 with a remainder of 7.
Use 1 as the next digit of our solution. 
Result so far: 1.0
The remainder is 7 after subtracting 21 from 28.
Append the next digit (7) from the dividend to 7 and continue with: 77 / 21

Moving on to step 3:
The number 21 fits into 77 3 times, leaving a remainder of 14.
Record the quotient 3 as the next digit in the result. 
Result so far: 13.0
Deduct 63 from 77 and we're left with 14.
Bring next digit (2) of the dividend behind the 14 and repeat the process: 142 / 21

Advancing to step 4:
142 divided by 21 is 6 with a remainder of 16.
Write down 6 as next digit of the result. 
Result so far: 136.0
Deduct 126 from 142 and we're left with 16.
Fetch the next digit (7) from the dividend, attach it to 16 and continue: 167 / 21

Moving on to step 5:
When dividing 167 by 21, we get 7 with a remainder of 20.
Record the quotient 7 as the next digit in the result. 
Result so far: 1367.0
Subtracting 147 from 167 leaves us with 20.
Include the next digit (4) from the dividend after 20, then repeat: 204 / 21

Advancing to step 6:
204 divided by 21 is 9 with a remainder of 15.
The next digit of our result is 9. 
Result so far: 13679.0
Subtracting 189 from 204 leaves us with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 7:
21 can be fit into 150 7 times, resulting in a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 13679.7
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.

On to step 8:
21 can be fit into 30 1 times, resulting in a remainder of 9.
Write down 1 as next digit of the result. 
Result so far: 13679.71
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.

Moving on to step 9:
90 divided by 21 is 4 with a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 13679.714
If we subtract 84 from 90, we 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.

Going ahead to step 10:
21 goes into 60 2 times with a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 13679.7142
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.

Moving on to step 11:
The number 21 fits into 180 8 times, leaving a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 13679.71428
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Moving on to step 12:
When dividing 120 by 21, we get 5 with a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 13679.714285
Subtracting 105 from 120 leaves us with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 13:
The number 21 fits into 150 7 times, leaving a remainder of 3.
Use 7 as the next digit of our solution. 
Result so far: 13679.7142857
Subtract 147 from 150 to get 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 14:
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: 13679.71428571
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.

After the division, we end up with 13679.71428571 and a remainder of 9e-09.