We look at the division of 723729 by 66 
The aim is to understand the frequency of 66 in 723729.

Going ahead to step 1:
66 goes into 7 0 times with a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Fetch the next digit (2) from the dividend, attach it to 7 and continue: 72 / 66

Moving on to step 2:
When dividing 72 by 66, we get 1 with a remainder of 6.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Subtract 66 from 72 to get 6.
Take the next digit (3) from the dividend and append it to 6, then repeat: 63 / 66

On to step 3:
When dividing 63 by 66, we get 0 with a remainder of 63.
Record the quotient 0 as the next digit in the result. 
Result so far: 10.0
Deduct 0 from 63 and we're left with 63.
Take the next digit (7) from the dividend and append it to 63, then repeat: 637 / 66

Going ahead to step 4:
66 goes into 637 9 times with a remainder of 43.
Record the quotient 9 as the next digit in the result. 
Result so far: 109.0
Deduct 594 from 637 and we're left with 43.
Fetch the next digit (2) from the dividend, attach it to 43 and continue: 432 / 66

Let's proceed to step 5:
If we divide 432 by 66, we get 6 and a remainder of 36.
The next digit of our result is 6. 
Result so far: 1096.0
If we subtract 396 from 432, we get 36.
Take the next digit (9) from the dividend and append it to 36, then repeat: 369 / 66

On to step 6:
The number 66 fits into 369 5 times, leaving a remainder of 39.
Record the quotient 5 as the next digit in the result. 
Result so far: 10965.0
If we subtract 330 from 369, we get 39.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

Advancing to step 7:
When dividing 390 by 66, we get 5 with a remainder of 60.
Use 5 as the next digit of our solution. 
Result so far: 10965.5
Subtracting 330 from 390 leaves us with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Going ahead to step 8:
The number 66 fits into 600 9 times, leaving a remainder of 6.
Record the quotient 9 as the next digit in the result. 
Result so far: 10965.59
If we subtract 594 from 600, we 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.

Advancing to step 9:
60 divided by 66 is 0 with a remainder of 60.
The next digit of our result is 0. 
Result so far: 10965.59
The remainder is 60 after subtracting 0 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Going ahead to step 10:
When dividing 600 by 66, we get 9 with a remainder of 6.
Record the quotient 9 as the next digit in the result. 
Result so far: 10965.5909
Subtract 594 from 600 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.

Step 11:
The number 66 fits into 60 0 times, leaving a remainder of 60.
The next digit of our result is 0. 
Result so far: 10965.5909
The remainder is 60 after subtracting 0 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Step 12:
When dividing 600 by 66, we get 9 with a remainder of 6.
The number 9 becomes the next digit in our result. 
Result so far: 10965.590909
Subtract 594 from 600 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.

Advancing to step 13:
When dividing 60 by 66, we get 0 with a remainder of 60.
Write down 0 as next digit of the result. 
Result so far: 10965.590909
The remainder is 60 after subtracting 0 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Step 14:
66 can be fit into 600 9 times, resulting in a remainder of 6.
Put 9 as the next digit of the answer. 
Result so far: 10965.59090909
Deduct 594 from 600 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

The final outcome is 10965.59090909, with a leftover of 6e-09.