Let's divide 801551 by 66
The aim is to understand the frequency of 66 in 801551.

Step 1:
66 can be fit into 8 0 times, resulting in a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Take the next digit (0) from the dividend and append it to 8, then repeat: 80 / 66

On to step 2:
80 divided by 66 is 1 with a remainder of 14.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
If we take 66 away from 80, we end up with 14.
Bring next digit (1) of the dividend behind the 14 and repeat the process: 141 / 66

Going ahead to step 3:
141 divided by 66 is 2 with a remainder of 9.
The number 2 becomes the next digit in our result. 
Result so far: 12.0
If we subtract 132 from 141, we get 9.
Append the next digit (5) from the dividend to 9 and continue with: 95 / 66

Step 4:
95 divided by 66 is 1 with a remainder of 29.
Record the quotient 1 as the next digit in the result. 
Result so far: 121.0
If we subtract 66 from 95, we get 29.
Take the next digit (5) from the dividend and append it to 29, then repeat: 295 / 66

Let's proceed to step 5:
The number 66 fits into 295 4 times, leaving a remainder of 31.
Put 4 as the next digit of the answer. 
Result so far: 1214.0
Subtract 264 from 295 to get 31.
Append the next digit (1) from the dividend to 31 and continue with: 311 / 66

Advancing to step 6:
The number 66 fits into 311 4 times, leaving a remainder of 47.
The next digit of our result is 4. 
Result so far: 12144.0
The remainder is 47 after subtracting 264 from 311.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

Step 7:
66 can be fit into 470 7 times, resulting in a remainder of 8.
The number 7 becomes the next digit in our result. 
Result so far: 12144.7
Subtracting 462 from 470 leaves us with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 8:
If we divide 80 by 66, we get 1 and a remainder of 14.
The number 1 becomes the next digit in our result. 
Result so far: 12144.71
Deduct 66 from 80 and we're left with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Moving on to step 9:
66 goes into 140 2 times with a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 12144.712
Subtract 132 from 140 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

On to step 10:
If we divide 80 by 66, we get 1 and a remainder of 14.
Write down 1 as next digit of the result. 
Result so far: 12144.7121
The remainder is 14 after subtracting 66 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Let's proceed to step 11:
The number 66 fits into 140 2 times, leaving a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 12144.71212
The remainder is 8 after subtracting 132 from 140.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 12:
66 goes into 80 1 times with a remainder of 14.
Record the quotient 1 as the next digit in the result. 
Result so far: 12144.712121
The remainder is 14 after subtracting 66 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Going ahead to step 13:
66 goes into 140 2 times with a remainder of 8.
The next digit of our result is 2. 
Result so far: 12144.7121212
If we take 132 away from 140, we end up with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

On to step 14:
The number 66 fits into 80 1 times, leaving a remainder of 14.
Write down 1 as next digit of the result. 
Result so far: 12144.71212121
If we subtract 66 from 80, we get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

The final result is 12144.71212121 with a remainder of 1.4e-08.