777284 ÷ 21 
The aim is to understand the frequency of 21 in 777284.

Step 1:
21 goes into 7 0 times with a remainder of 7.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 7 leaves us with 7.
Append the next digit (7) from the dividend to 7 and continue with: 77 / 21

Going ahead to step 2:
When dividing 77 by 21, we get 3 with a remainder of 14.
Use 3 as the next digit of our solution. 
Result so far: 3.0
Subtracting 63 from 77 leaves us with 14.
Include the next digit (7) from the dividend after 14, then repeat: 147 / 21

On to step 3:
21 can be fit into 147 7 times, resulting in a remainder of 0.
Record the quotient 7 as the next digit in the result. 
Result so far: 37.0
Subtract 147 from 147 to get 0.
Fetch the next digit (2) from the dividend, attach it to 0 and continue: 2 / 21

Let's proceed to step 4:
21 goes into 2 0 times with a remainder of 2.
The number 0 becomes the next digit in our result. 
Result so far: 370.0
Subtracting 0 from 2 leaves us with 2.
Append the next digit (8) from the dividend to 2 and continue with: 28 / 21

Going ahead to step 5:
The number 21 fits into 28 1 times, leaving a remainder of 7.
The number 1 becomes the next digit in our result. 
Result so far: 3701.0
Deduct 21 from 28 and we're left with 7.
Grab the next digit (4) from the dividend, add it to 7, then carry on: 74 / 21

On to step 6:
21 goes into 74 3 times with a remainder of 11.
Write down 3 as next digit of the result. 
Result so far: 37013.0
Subtract 63 from 74 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.

Moving on to step 7:
21 goes into 110 5 times with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 37013.5
Deduct 105 from 110 and we're left 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:
The number 21 fits into 50 2 times, leaving a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 37013.52
Deduct 42 from 50 and we're left with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Moving on to step 9:
If we divide 80 by 21, we get 3 and a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 37013.523
The remainder is 17 after subtracting 63 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Advancing to step 10:
170 divided by 21 is 8 with a remainder of 2.
Use 8 as the next digit of our solution. 
Result so far: 37013.5238
Subtracting 168 from 170 leaves us with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Moving on to step 11:
21 can be fit into 20 0 times, resulting in a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 37013.5238
The remainder is 20 after subtracting 0 from 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

On to step 12:
If we divide 200 by 21, we get 9 and a remainder of 11.
The next digit of our result is 9. 
Result so far: 37013.523809
Deduct 189 from 200 and we're left 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.

Going ahead to step 13:
21 can be fit into 110 5 times, resulting in a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 37013.5238095
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.

On to step 14:
50 divided by 21 is 2 with a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 37013.52380952
Deduct 42 from 50 and we're left with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Our division results in 37013.52380952 with a remaining 8e-09.