Let's divide 355791 by 66
The aim is to understand the frequency of 66 in 355791.

Advancing to step 1:
66 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
If we take 0 away from 3, we end up with 3.
Include the next digit (5) from the dividend after 3, then repeat: 35 / 66

Going ahead to step 2:
The number 66 fits into 35 0 times, leaving a remainder of 35.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 35 after subtracting 0 from 35.
Append the next digit (5) from the dividend to 35 and continue with: 355 / 66

Let's proceed to step 3:
When dividing 355 by 66, we get 5 with a remainder of 25.
Record the quotient 5 as the next digit in the result. 
Result so far: 5.0
If we take 330 away from 355, we end up with 25.
Fetch the next digit (7) from the dividend, attach it to 25 and continue: 257 / 66

Step 4:
If we divide 257 by 66, we get 3 and a remainder of 59.
Put 3 as the next digit of the answer. 
Result so far: 53.0
If we take 198 away from 257, we end up with 59.
Append the next digit (9) from the dividend to 59 and continue with: 599 / 66

Advancing to step 5:
The number 66 fits into 599 9 times, leaving a remainder of 5.
Record the quotient 9 as the next digit in the result. 
Result so far: 539.0
Subtracting 594 from 599 leaves us with 5.
Grab the next digit (1) from the dividend, add it to 5, then carry on: 51 / 66

Moving on to step 6:
The number 66 fits into 51 0 times, leaving a remainder of 51.
Use 0 as the next digit of our solution. 
Result so far: 5390.0
If we take 0 away from 51, we end up with 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

Advancing to step 7:
66 can be fit into 510 7 times, resulting in a remainder of 48.
The number 7 becomes the next digit in our result. 
Result so far: 5390.7
Subtracting 462 from 510 leaves us with 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

Step 8:
66 goes into 480 7 times with a remainder of 18.
Use 7 as the next digit of our solution. 
Result so far: 5390.77
Deduct 462 from 480 and we're left 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.

The quotient of the division is 5390.77, and the remainder is 0.018.