We look at the division of 345969 by 66 
The aim is to understand the frequency of 66 in 345969.

Step 1:
When dividing 3 by 66, we get 0 with a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Take the next digit (4) from the dividend and append it to 3, then repeat: 34 / 66

Let's proceed to step 2:
66 can be fit into 34 0 times, resulting in a remainder of 34.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 34 to get 34.
Fetch the next digit (5) from the dividend, attach it to 34 and continue: 345 / 66

Let's proceed to step 3:
The number 66 fits into 345 5 times, leaving a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 5.0
If we subtract 330 from 345, we get 15.
Fetch the next digit (9) from the dividend, attach it to 15 and continue: 159 / 66

Advancing to step 4:
159 divided by 66 is 2 with a remainder of 27.
Record the quotient 2 as the next digit in the result. 
Result so far: 52.0
Subtracting 132 from 159 leaves us with 27.
Append the next digit (6) from the dividend to 27 and continue with: 276 / 66

Advancing to step 5:
276 divided by 66 is 4 with a remainder of 12.
Put 4 as the next digit of the answer. 
Result so far: 524.0
If we subtract 264 from 276, we get 12.
Append the next digit (9) from the dividend to 12 and continue with: 129 / 66

Moving on to step 6:
66 goes into 129 1 times with a remainder of 63.
The number 1 becomes the next digit in our result. 
Result so far: 5241.0
Subtracting 66 from 129 leaves us with 63.
Since there are no more digits in the dividend, we add a zero to the remainder making it 630, and continue the process.

Step 7:
66 goes into 630 9 times with a remainder of 36.
The number 9 becomes the next digit in our result. 
Result so far: 5241.9
Deduct 594 from 630 and we're left with 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Step 8:
The number 66 fits into 360 5 times, leaving a remainder of 30.
The number 5 becomes the next digit in our result. 
Result so far: 5241.95
Deduct 330 from 360 and we're left with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Moving on to step 9:
When dividing 300 by 66, we get 4 with a remainder of 36.
The next digit of our result is 4. 
Result so far: 5241.954
Deduct 264 from 300 and we're left with 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Moving on to step 10:
66 goes into 360 5 times with a remainder of 30.
Put 5 as the next digit of the answer. 
Result so far: 5241.9545
Subtracting 330 from 360 leaves us with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Let's proceed to step 11:
If we divide 300 by 66, we get 4 and a remainder of 36.
The next digit of our result is 4. 
Result so far: 5241.95454
Deduct 264 from 300 and we're left with 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Step 12:
66 can be fit into 360 5 times, resulting in a remainder of 30.
Write down 5 as next digit of the result. 
Result so far: 5241.954545
The remainder is 30 after subtracting 330 from 360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

On to step 13:
66 goes into 300 4 times with a remainder of 36.
The next digit of our result is 4. 
Result so far: 5241.9545454
The remainder is 36 after subtracting 264 from 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Advancing to step 14:
The number 66 fits into 360 5 times, leaving a remainder of 30.
The next digit of our result is 5. 
Result so far: 5241.95454545
Subtract 330 from 360 to get 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

After the division, we end up with 5241.95454545 and a remainder of 3e-08.