We divide 71556 by 21
The aim is to understand the frequency of 21 in 71556.

Advancing to step 1:
If we divide 7 by 21, we get 0 and a remainder of 7.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Append the next digit (1) from the dividend to 7 and continue with: 71 / 21

Going ahead to step 2:
21 can be fit into 71 3 times, resulting in a remainder of 8.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
Subtracting 63 from 71 leaves us with 8.
Fetch the next digit (5) from the dividend, attach it to 8 and continue: 85 / 21

On to step 3:
85 divided by 21 is 4 with a remainder of 1.
Use 4 as the next digit of our solution. 
Result so far: 34.0
The remainder is 1 after subtracting 84 from 85.
Take the next digit (5) from the dividend and append it to 1, then repeat: 15 / 21

Advancing to step 4:
The number 21 fits into 15 0 times, leaving a remainder of 15.
The number 0 becomes the next digit in our result. 
Result so far: 340.0
Subtract 0 from 15 to get 15.
Include the next digit (6) from the dividend after 15, then repeat: 156 / 21

Step 5:
If we divide 156 by 21, we get 7 and a remainder of 9.
Put 7 as the next digit of the answer. 
Result so far: 3407.0
The remainder is 9 after subtracting 147 from 156.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Going ahead to step 6:
The number 21 fits into 90 4 times, leaving a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 3407.4
If we take 84 away from 90, we end up 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.

Advancing to step 7:
When dividing 60 by 21, we get 2 with a remainder of 18.
Put 2 as the next digit of the answer. 
Result so far: 3407.42
If we subtract 42 from 60, we get 18.
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 8:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 3407.428
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.

Let's proceed to step 9:
When dividing 120 by 21, we get 5 with a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 3407.4285
Deduct 105 from 120 and we're left 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.

Moving on to step 10:
The number 21 fits into 150 7 times, leaving a remainder of 3.
The number 7 becomes the next digit in our result. 
Result so far: 3407.42857
The remainder is 3 after subtracting 147 from 150.
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 11:
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: 3407.428571
Subtracting 21 from 30 leaves us 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 12:
21 can be fit into 90 4 times, resulting in a remainder of 6.
The next digit of our result is 4. 
Result so far: 3407.4285714
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.

Advancing to step 13:
60 divided by 21 is 2 with a remainder of 18.
The next digit of our result is 2. 
Result so far: 3407.42857142
If we take 42 away from 60, we end up 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 3407.42857142, and the remainder is 1.8e-08.