775856 divided by 21 
The aim is to understand the frequency of 21 in 775856.

Moving on to step 1:
The number 21 fits into 7 0 times, leaving a remainder of 7.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Fetch the next digit (7) from the dividend, attach it to 7 and continue: 77 / 21

Going ahead to step 2:
77 divided by 21 is 3 with a remainder of 14.
Use 3 as the next digit of our solution. 
Result so far: 3.0
The remainder is 14 after subtracting 63 from 77.
Append the next digit (5) from the dividend to 14 and continue with: 145 / 21

Advancing to step 3:
21 goes into 145 6 times with a remainder of 19.
Record the quotient 6 as the next digit in the result. 
Result so far: 36.0
Subtract 126 from 145 to get 19.
Bring next digit (8) of the dividend behind the 19 and repeat the process: 198 / 21

Step 4:
The number 21 fits into 198 9 times, leaving a remainder of 9.
The number 9 becomes the next digit in our result. 
Result so far: 369.0
Subtracting 189 from 198 leaves us with 9.
Fetch the next digit (5) from the dividend, attach it to 9 and continue: 95 / 21

Step 5:
21 can be fit into 95 4 times, resulting in a remainder of 11.
Record the quotient 4 as the next digit in the result. 
Result so far: 3694.0
Deduct 84 from 95 and we're left with 11.
Bring next digit (6) of the dividend behind the 11 and repeat the process: 116 / 21

On to step 6:
21 goes into 116 5 times with a remainder of 11.
The number 5 becomes the next digit in our result. 
Result so far: 36945.0
Subtracting 105 from 116 leaves us with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Let's proceed to step 7:
21 can be fit into 110 5 times, resulting in a remainder of 5.
Use 5 as the next digit of our solution. 
Result so far: 36945.5
If we take 105 away from 110, we end up with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 8:
50 divided by 21 is 2 with a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 36945.52
The remainder is 8 after subtracting 42 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Advancing to step 9:
If we divide 80 by 21, we get 3 and a remainder of 17.
Use 3 as the next digit of our solution. 
Result so far: 36945.523
If we take 63 away from 80, we end up with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Let's proceed to step 10:
21 can be fit into 170 8 times, resulting in a remainder of 2.
Record the quotient 8 as the next digit in the result. 
Result so far: 36945.5238
Subtract 168 from 170 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Let's proceed to step 11:
21 can be fit into 20 0 times, resulting in a remainder of 20.
The next digit of our result is 0. 
Result so far: 36945.5238
If we subtract 0 from 20, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 12:
21 goes into 200 9 times with a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 36945.523809
Subtract 189 from 200 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 13:
If we divide 110 by 21, we get 5 and a remainder of 5.
The next digit of our result is 5. 
Result so far: 36945.5238095
Subtracting 105 from 110 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Moving on to step 14:
21 goes into 50 2 times with a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 36945.52380952
Subtract 42 from 50 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

The final outcome is 36945.52380952, with a leftover of 8e-09.