We're dividing 346653 by 21 
The aim is to understand the frequency of 21 in 346653.

Advancing to step 1:
21 goes into 3 0 times with a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 3 after subtracting 0 from 3.
Append the next digit (4) from the dividend to 3 and continue with: 34 / 21

Going ahead to step 2:
The number 21 fits into 34 1 times, leaving a remainder of 13.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtracting 21 from 34 leaves us with 13.
Take the next digit (6) from the dividend and append it to 13, then repeat: 136 / 21

Let's proceed to step 3:
The number 21 fits into 136 6 times, leaving a remainder of 10.
Record the quotient 6 as the next digit in the result. 
Result so far: 16.0
If we subtract 126 from 136, we get 10.
Append the next digit (6) from the dividend to 10 and continue with: 106 / 21

Step 4:
21 goes into 106 5 times with a remainder of 1.
Use 5 as the next digit of our solution. 
Result so far: 165.0
Subtract 105 from 106 to get 1.
Include the next digit (5) from the dividend after 1, then repeat: 15 / 21

Advancing to step 5:
21 goes into 15 0 times with a remainder of 15.
The number 0 becomes the next digit in our result. 
Result so far: 1650.0
The remainder is 15 after subtracting 0 from 15.
Bring next digit (3) of the dividend behind the 15 and repeat the process: 153 / 21

Advancing to step 6:
21 goes into 153 7 times with a remainder of 6.
The next digit of our result is 7. 
Result so far: 16507.0
Subtract 147 from 153 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 7:
21 goes into 60 2 times with a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 16507.2
Subtracting 42 from 60 leaves us 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.

On to step 8:
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: 16507.28
Subtract 168 from 180 to 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.

Let's proceed to step 9:
The number 21 fits into 120 5 times, leaving a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 16507.285
If we subtract 105 from 120, we get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 10:
The number 21 fits into 150 7 times, leaving a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 16507.2857
The remainder is 3 after subtracting 147 from 150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 11:
The number 21 fits into 30 1 times, leaving a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 16507.28571
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.

Let's proceed to step 12:
The number 21 fits into 90 4 times, leaving a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 16507.285714
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.

On to step 13:
When dividing 60 by 21, we get 2 with a remainder of 18.
Record the quotient 2 as the next digit in the result. 
Result so far: 16507.2857142
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.

Step 14:
When dividing 180 by 21, we get 8 with a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 16507.28571428
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.

The final outcome is 16507.28571428, with a leftover of 1.2e-08.