We look at the division of 878725 by 66 
The aim is to understand the frequency of 66 in 878725.

On to step 1:
If we divide 8 by 66, we get 0 and a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Take the next digit (7) from the dividend and append it to 8, then repeat: 87 / 66

On to step 2:
When dividing 87 by 66, we get 1 with a remainder of 21.
Write down 1 as next digit of the result. 
Result so far: 1.0
If we subtract 66 from 87, we get 21.
Include the next digit (8) from the dividend after 21, then repeat: 218 / 66

On to step 3:
66 goes into 218 3 times with a remainder of 20.
Put 3 as the next digit of the answer. 
Result so far: 13.0
The remainder is 20 after subtracting 198 from 218.
Append the next digit (7) from the dividend to 20 and continue with: 207 / 66

Moving on to step 4:
66 goes into 207 3 times with a remainder of 9.
The number 3 becomes the next digit in our result. 
Result so far: 133.0
Subtracting 198 from 207 leaves us with 9.
Take the next digit (2) from the dividend and append it to 9, then repeat: 92 / 66

Advancing to step 5:
92 divided by 66 is 1 with a remainder of 26.
Write down 1 as next digit of the result. 
Result so far: 1331.0
Subtract 66 from 92 to get 26.
Append the next digit (5) from the dividend to 26 and continue with: 265 / 66

Advancing to step 6:
265 divided by 66 is 4 with a remainder of 1.
Put 4 as the next digit of the answer. 
Result so far: 13314.0
Subtract 264 from 265 to get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 7:
If we divide 10 by 66, we get 0 and a remainder of 10.
The next digit of our result is 0. 
Result so far: 13314.0
If we subtract 0 from 10, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 8:
If we divide 100 by 66, we get 1 and a remainder of 34.
Put 1 as the next digit of the answer. 
Result so far: 13314.01
The remainder is 34 after subtracting 66 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

Step 9:
66 can be fit into 340 5 times, resulting in a remainder of 10.
Put 5 as the next digit of the answer. 
Result so far: 13314.015
Subtract 330 from 340 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 10:
100 divided by 66 is 1 with a remainder of 34.
Put 1 as the next digit of the answer. 
Result so far: 13314.0151
Deduct 66 from 100 and we're left with 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

On to step 11:
The number 66 fits into 340 5 times, leaving a remainder of 10.
Put 5 as the next digit of the answer. 
Result so far: 13314.01515
Subtract 330 from 340 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Moving on to step 12:
66 can be fit into 100 1 times, resulting in a remainder of 34.
Record the quotient 1 as the next digit in the result. 
Result so far: 13314.015151
The remainder is 34 after subtracting 66 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

Let's proceed to step 13:
The number 66 fits into 340 5 times, leaving a remainder of 10.
Put 5 as the next digit of the answer. 
Result so far: 13314.0151515
The remainder is 10 after subtracting 330 from 340.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 14:
If we divide 100 by 66, we get 1 and a remainder of 34.
Use 1 as the next digit of our solution. 
Result so far: 13314.01515151
Deduct 66 from 100 and we're left with 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

The final result is 13314.01515151 with a remainder of 3.4e-08.