We divide 775560 by 21
The aim is to understand the frequency of 21 in 775560.

Advancing to step 1:
If we divide 7 by 21, we get 0 and a remainder of 7.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 7, we end up with 7.
Take the next digit (7) from the dividend and append it to 7, then repeat: 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
If we subtract 63 from 77, we get 14.
Grab the next digit (5) from the dividend, add it to 14, then carry on: 145 / 21

Step 3:
21 goes into 145 6 times with a remainder of 19.
The next digit of our result is 6. 
Result so far: 36.0
Deduct 126 from 145 and we're left with 19.
Fetch the next digit (5) from the dividend, attach it to 19 and continue: 195 / 21

Step 4:
If we divide 195 by 21, we get 9 and a remainder of 6.
Write down 9 as next digit of the result. 
Result so far: 369.0
If we take 189 away from 195, we end up with 6.
Fetch the next digit (6) from the dividend, attach it to 6 and continue: 66 / 21

Going ahead to step 5:
The number 21 fits into 66 3 times, leaving a remainder of 3.
Record the quotient 3 as the next digit in the result. 
Result so far: 3693.0
If we take 63 away from 66, we end up with 3.
Append the next digit (0) from the dividend to 3 and continue with: 30 / 21

Let's proceed to step 6:
The number 21 fits into 30 1 times, leaving a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 36931.0
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.

On to step 7:
The number 21 fits into 90 4 times, leaving a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 36931.4
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.

Let's proceed to step 8:
The number 21 fits into 60 2 times, leaving a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 36931.42
Subtract 42 from 60 to 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.

Moving on to step 9:
21 can be fit into 180 8 times, resulting in a remainder of 12.
The next digit of our result is 8. 
Result so far: 36931.428
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 10:
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: 36931.4285
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.

Let's proceed to step 11:
21 goes into 150 7 times with a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 36931.42857
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.

Step 12:
The number 21 fits into 30 1 times, leaving a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 36931.428571
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.

Step 13:
90 divided by 21 is 4 with a remainder of 6.
The number 4 becomes the next digit in our result. 
Result so far: 36931.4285714
Subtracting 84 from 90 leaves us 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 14:
If we divide 60 by 21, we get 2 and a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 36931.42857142
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 final result is 36931.42857142 with a remainder of 1.8e-08.