274120 divided by 21 
The aim is to understand the frequency of 21 in 274120.

On to step 1:
If we divide 2 by 21, we get 0 and a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 2 leaves us with 2.
Bring next digit (7) of the dividend behind the 2 and repeat the process: 27 / 21

Advancing to step 2:
21 goes into 27 1 times with a remainder of 6.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Deduct 21 from 27 and we're left with 6.
Append the next digit (4) from the dividend to 6 and continue with: 64 / 21

Step 3:
21 can be fit into 64 3 times, resulting in a remainder of 1.
The number 3 becomes the next digit in our result. 
Result so far: 13.0
If we subtract 63 from 64, we get 1.
Append the next digit (1) from the dividend to 1 and continue with: 11 / 21

Moving on to step 4:
11 divided by 21 is 0 with a remainder of 11.
Record the quotient 0 as the next digit in the result. 
Result so far: 130.0
Deduct 0 from 11 and we're left with 11.
Bring next digit (2) of the dividend behind the 11 and repeat the process: 112 / 21

Advancing to step 5:
If we divide 112 by 21, we get 5 and a remainder of 7.
Put 5 as the next digit of the answer. 
Result so far: 1305.0
If we subtract 105 from 112, we get 7.
Fetch the next digit (0) from the dividend, attach it to 7 and continue: 70 / 21

Moving on to step 6:
If we divide 70 by 21, we get 3 and a remainder of 7.
Use 3 as the next digit of our solution. 
Result so far: 13053.0
The remainder is 7 after subtracting 63 from 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Step 7:
When dividing 70 by 21, we get 3 with a remainder of 7.
The number 3 becomes the next digit in our result. 
Result so far: 13053.3
If we take 63 away from 70, we end up with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Advancing to step 8:
When dividing 70 by 21, we get 3 with a remainder of 7.
The number 3 becomes the next digit in our result. 
Result so far: 13053.33
Deduct 63 from 70 and we're left with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

After the division, we end up with 13053.33 and a remainder of 0.007.