Let's divide 729880 by 21
The aim is to understand the frequency of 21 in 729880.

Let's proceed to step 1:
If we divide 7 by 21, we get 0 and a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 7 to get 7.
Fetch the next digit (2) from the dividend, attach it to 7 and continue: 72 / 21

On to step 2:
The number 21 fits into 72 3 times, leaving a remainder of 9.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
If we subtract 63 from 72, we get 9.
Grab the next digit (9) from the dividend, add it to 9, then carry on: 99 / 21

Step 3:
If we divide 99 by 21, we get 4 and a remainder of 15.
The next digit of our result is 4. 
Result so far: 34.0
Deduct 84 from 99 and we're left with 15.
Append the next digit (8) from the dividend to 15 and continue with: 158 / 21

Let's proceed to step 4:
The number 21 fits into 158 7 times, leaving a remainder of 11.
Record the quotient 7 as the next digit in the result. 
Result so far: 347.0
If we take 147 away from 158, we end up with 11.
Include the next digit (8) from the dividend after 11, then repeat: 118 / 21

Let's proceed to step 5:
If we divide 118 by 21, we get 5 and a remainder of 13.
The number 5 becomes the next digit in our result. 
Result so far: 3475.0
If we subtract 105 from 118, we get 13.
Include the next digit (0) from the dividend after 13, then repeat: 130 / 21

Let's proceed to step 6:
When dividing 130 by 21, we get 6 with a remainder of 4.
Put 6 as the next digit of the answer. 
Result so far: 34756.0
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.

Step 7:
If we divide 40 by 21, we get 1 and a remainder of 19.
Write down 1 as next digit of the result. 
Result so far: 34756.1
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.

Let's proceed to step 8:
If we divide 190 by 21, we get 9 and a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 34756.19
Subtracting 189 from 190 leaves us 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 9:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 34756.19
The remainder is 10 after subtracting 0 from 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Moving on to step 10:
100 divided by 21 is 4 with a remainder of 16.
Write down 4 as next digit of the result. 
Result so far: 34756.1904
Deduct 84 from 100 and we're left 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.

Going ahead to step 11:
When dividing 160 by 21, we get 7 with a remainder of 13.
Record the quotient 7 as the next digit in the result. 
Result so far: 34756.19047
Subtract 147 from 160 to 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.

Let's proceed to step 12:
21 goes into 130 6 times with a remainder of 4.
The next digit of our result is 6. 
Result so far: 34756.190476
Subtracting 126 from 130 leaves us 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.

Moving on to step 13:
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: 34756.1904761
Subtracting 21 from 40 leaves us 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.

Advancing to step 14:
The number 21 fits into 190 9 times, leaving a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 34756.19047619
If we subtract 189 from 190, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

The final outcome is 34756.19047619, with a leftover of 1e-09.