We look at the division of 263316 by 66 
The aim is to understand the frequency of 66 in 263316.

On to step 1:
66 goes into 2 0 times with a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 2 leaves us with 2.
Append the next digit (6) from the dividend to 2 and continue with: 26 / 66

Let's proceed to step 2:
66 can be fit into 26 0 times, resulting in a remainder of 26.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 26, we get 26.
Grab the next digit (3) from the dividend, add it to 26, then carry on: 263 / 66

Step 3:
263 divided by 66 is 3 with a remainder of 65.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
If we take 198 away from 263, we end up with 65.
Fetch the next digit (3) from the dividend, attach it to 65 and continue: 653 / 66

Step 4:
If we divide 653 by 66, we get 9 and a remainder of 59.
The number 9 becomes the next digit in our result. 
Result so far: 39.0
Deduct 594 from 653 and we're left with 59.
Bring next digit (1) of the dividend behind the 59 and repeat the process: 591 / 66

Advancing to step 5:
66 can be fit into 591 8 times, resulting in a remainder of 63.
Put 8 as the next digit of the answer. 
Result so far: 398.0
If we take 528 away from 591, we end up with 63.
Grab the next digit (6) from the dividend, add it to 63, then carry on: 636 / 66

On to step 6:
66 goes into 636 9 times with a remainder of 42.
Put 9 as the next digit of the answer. 
Result so far: 3989.0
Deduct 594 from 636 and we're left with 42.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

On to step 7:
When dividing 420 by 66, we get 6 with a remainder of 24.
Use 6 as the next digit of our solution. 
Result so far: 3989.6
The remainder is 24 after subtracting 396 from 420.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Moving on to step 8:
If we divide 240 by 66, we get 3 and a remainder of 42.
Record the quotient 3 as the next digit in the result. 
Result so far: 3989.63
Subtract 198 from 240 to get 42.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

Advancing to step 9:
420 divided by 66 is 6 with a remainder of 24.
Put 6 as the next digit of the answer. 
Result so far: 3989.636
If we subtract 396 from 420, we get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

On to step 10:
The number 66 fits into 240 3 times, leaving a remainder of 42.
Write down 3 as next digit of the result. 
Result so far: 3989.6363
Deduct 198 from 240 and we're left with 42.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

Let's proceed to step 11:
66 can be fit into 420 6 times, resulting in a remainder of 24.
The next digit of our result is 6. 
Result so far: 3989.63636
Deduct 396 from 420 and we're left with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Going ahead to step 12:
The number 66 fits into 240 3 times, leaving a remainder of 42.
Write down 3 as next digit of the result. 
Result so far: 3989.636363
Deduct 198 from 240 and we're left with 42.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

Going ahead to step 13:
66 goes into 420 6 times with a remainder of 24.
The number 6 becomes the next digit in our result. 
Result so far: 3989.6363636
The remainder is 24 after subtracting 396 from 420.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Moving on to step 14:
When dividing 240 by 66, we get 3 with a remainder of 42.
The next digit of our result is 3. 
Result so far: 3989.63636363
Subtract 198 from 240 to get 42.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

The final outcome is 3989.63636363, with a leftover of 4.2e-08.