Let's divide 788416 by 21
The aim is to understand the frequency of 21 in 788416.

On to step 1:
21 can be fit into 7 0 times, resulting in 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.
Take the next digit (8) from the dividend and append it to 7, then repeat: 78 / 21

Step 2:
The number 21 fits into 78 3 times, leaving a remainder of 15.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
Subtracting 63 from 78 leaves us with 15.
Include the next digit (8) from the dividend after 15, then repeat: 158 / 21

On to step 3:
158 divided by 21 is 7 with a remainder of 11.
Put 7 as the next digit of the answer. 
Result so far: 37.0
Subtracting 147 from 158 leaves us with 11.
Bring next digit (4) of the dividend behind the 11 and repeat the process: 114 / 21

On to step 4:
114 divided by 21 is 5 with a remainder of 9.
Put 5 as the next digit of the answer. 
Result so far: 375.0
If we take 105 away from 114, we end up with 9.
Fetch the next digit (1) from the dividend, attach it to 9 and continue: 91 / 21

Step 5:
21 goes into 91 4 times with a remainder of 7.
Put 4 as the next digit of the answer. 
Result so far: 3754.0
If we subtract 84 from 91, we get 7.
Take the next digit (6) from the dividend and append it to 7, then repeat: 76 / 21

Let's proceed to step 6:
21 can be fit into 76 3 times, resulting in a remainder of 13.
Use 3 as the next digit of our solution. 
Result so far: 37543.0
Deduct 63 from 76 and we're left with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Let's proceed to step 7:
21 goes into 130 6 times with a remainder of 4.
Put 6 as the next digit of the answer. 
Result so far: 37543.6
If we take 126 away from 130, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 8:
21 goes into 40 1 times with a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 37543.61
If we subtract 21 from 40, we get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Moving on to step 9:
The number 21 fits into 190 9 times, leaving a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 37543.619
Deduct 189 from 190 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 10:
The number 21 fits into 10 0 times, leaving a remainder of 10.
The next digit of our result is 0. 
Result so far: 37543.619
If we take 0 away from 10, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 11:
The number 21 fits into 100 4 times, leaving a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 37543.61904
If we take 84 away from 100, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Step 12:
21 can be fit into 160 7 times, resulting in a remainder of 13.
Write down 7 as next digit of the result. 
Result so far: 37543.619047
If we subtract 147 from 160, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 13:
The number 21 fits into 130 6 times, leaving a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 37543.6190476
If we subtract 126 from 130, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Advancing to step 14:
The number 21 fits into 40 1 times, leaving a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 37543.61904761
If we take 21 away from 40, we end up with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

The final outcome is 37543.61904761, with a leftover of 1.9e-08.