76830 divided by 21 
The aim is to understand the frequency of 21 in 76830.

Moving on 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 (6) from the dividend, add it to 7, then carry on: 76 / 21

Step 2:
If we divide 76 by 21, we get 3 and a remainder of 13.
Use 3 as the next digit of our solution. 
Result so far: 3.0
If we subtract 63 from 76, we get 13.
Include the next digit (8) from the dividend after 13, then repeat: 138 / 21

Going ahead to step 3:
21 goes into 138 6 times with a remainder of 12.
Put 6 as the next digit of the answer. 
Result so far: 36.0
Subtracting 126 from 138 leaves us with 12.
Fetch the next digit (3) from the dividend, attach it to 12 and continue: 123 / 21

Step 4:
The number 21 fits into 123 5 times, leaving a remainder of 18.
Use 5 as the next digit of our solution. 
Result so far: 365.0
Subtract 105 from 123 to get 18.
Take the next digit (0) from the dividend and append it to 18, then repeat: 180 / 21

Going ahead to step 5:
The number 21 fits into 180 8 times, leaving a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 3658.0
If we subtract 168 from 180, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 6:
21 can be fit into 120 5 times, resulting in a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 3658.5
If we take 105 away from 120, 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.

Step 7:
When dividing 150 by 21, we get 7 with a remainder of 3.
The next digit of our result is 7. 
Result so far: 3658.57
If we take 147 away from 150, we end up 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.

Step 8:
The number 21 fits into 30 1 times, leaving a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 3658.571
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.

Advancing to step 9:
90 divided by 21 is 4 with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 3658.5714
Subtract 84 from 90 to 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 10:
60 divided by 21 is 2 with a remainder of 18.
Record the quotient 2 as the next digit in the result. 
Result so far: 3658.57142
Deduct 42 from 60 and we're left 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.

Moving on to step 11:
When dividing 180 by 21, we get 8 with a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 3658.571428
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 12:
If we divide 120 by 21, we get 5 and a remainder of 15.
Use 5 as the next digit of our solution. 
Result so far: 3658.5714285
The remainder is 15 after subtracting 105 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Moving on to step 13:
When dividing 150 by 21, we get 7 with a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 3658.57142857
Deduct 147 from 150 and we're left 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.

The quotient of the division is 3658.57142857, and the remainder is 3e-09.