77127 divided by 21 
The aim is to understand the frequency of 21 in 77127.

Advancing to step 1:
When dividing 7 by 21, we get 0 with a remainder of 7.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 7 and we're left with 7.
Grab the next digit (7) from the dividend, add it to 7, then carry on: 77 / 21

Going ahead to step 2:
If we divide 77 by 21, we get 3 and a remainder of 14.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
Subtract 63 from 77 to get 14.
Append the next digit (1) from the dividend to 14 and continue with: 141 / 21

Step 3:
The number 21 fits into 141 6 times, leaving a remainder of 15.
Write down 6 as next digit of the result. 
Result so far: 36.0
The remainder is 15 after subtracting 126 from 141.
Bring next digit (2) of the dividend behind the 15 and repeat the process: 152 / 21

Going ahead to step 4:
The number 21 fits into 152 7 times, leaving a remainder of 5.
Record the quotient 7 as the next digit in the result. 
Result so far: 367.0
Subtracting 147 from 152 leaves us with 5.
Take the next digit (7) from the dividend and append it to 5, then repeat: 57 / 21

Let's proceed to step 5:
If we divide 57 by 21, we get 2 and a remainder of 15.
Use 2 as the next digit of our solution. 
Result so far: 3672.0
If we take 42 away from 57, we end up 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.

Going ahead to step 6:
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: 3672.7
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.

Let's proceed to step 7:
The number 21 fits into 30 1 times, leaving a remainder of 9.
The next digit of our result is 1. 
Result so far: 3672.71
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.

Moving on to step 8:
If we divide 90 by 21, we get 4 and a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 3672.714
The remainder is 6 after subtracting 84 from 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 9:
21 can be fit into 60 2 times, resulting in a remainder of 18.
The next digit of our result is 2. 
Result so far: 3672.7142
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.

Advancing to step 10:
21 goes into 180 8 times with a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 3672.71428
If we take 168 away from 180, we end up with 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 can be fit into 120 5 times, resulting in a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 3672.714285
If we subtract 105 from 120, we get 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 12:
The number 21 fits into 150 7 times, leaving a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 3672.7142857
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.

Let's proceed to step 13:
30 divided by 21 is 1 with a remainder of 9.
The next digit of our result is 1. 
Result so far: 3672.71428571
The remainder is 9 after subtracting 21 from 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

The final result is 3672.71428571 with a remainder of 9e-09.