We divide 66639920 by 666
The aim is to understand the frequency of 666 in 66639920.

On to step 1:
The number 666 fits into 6 0 times, leaving a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Include the next digit (6) from the dividend after 6, then repeat: 66 / 666

Advancing to step 2:
If we divide 66 by 666, we get 0 and a remainder of 66.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 66 to get 66.
Append the next digit (6) from the dividend to 66 and continue with: 666 / 666

On to step 3:
666 can be fit into 666 1 times, resulting in a remainder of 0.
The next digit of our result is 1. 
Result so far: 1.0
Subtracting 666 from 666 leaves us with 0.
Grab the next digit (3) from the dividend, add it to 0, then carry on: 3 / 666

On to step 4:
When dividing 3 by 666, we get 0 with a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 10.0
If we subtract 0 from 3, we get 3.
Fetch the next digit (9) from the dividend, attach it to 3 and continue: 39 / 666

On to step 5:
The number 666 fits into 39 0 times, leaving a remainder of 39.
The number 0 becomes the next digit in our result. 
Result so far: 100.0
The remainder is 39 after subtracting 0 from 39.
Append the next digit (9) from the dividend to 39 and continue with: 399 / 666

On to step 6:
666 goes into 399 0 times with a remainder of 399.
Write down 0 as next digit of the result. 
Result so far: 1000.0
Subtract 0 from 399 to get 399.
Take the next digit (2) from the dividend and append it to 399, then repeat: 3992 / 666

Going ahead to step 7:
When dividing 3992 by 666, we get 5 with a remainder of 662.
Put 5 as the next digit of the answer. 
Result so far: 10005.0
The remainder is 662 after subtracting 3330 from 3992.
Append the next digit (0) from the dividend to 662 and continue with: 6620 / 666

Going ahead to step 8:
The number 666 fits into 6620 9 times, leaving a remainder of 626.
The next digit of our result is 9. 
Result so far: 100059.0
Deduct 5994 from 6620 and we're left with 626.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6260, and continue the process.

Moving on to step 9:
If we divide 6260 by 666, we get 9 and a remainder of 266.
The next digit of our result is 9. 
Result so far: 100059.9
Subtracting 5994 from 6260 leaves us with 266.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2660, and continue the process.

Let's proceed to step 10:
666 goes into 2660 3 times with a remainder of 662.
Use 3 as the next digit of our solution. 
Result so far: 100059.93
Subtract 1998 from 2660 to get 662.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6620, and continue the process.

Advancing to step 11:
The number 666 fits into 6620 9 times, leaving a remainder of 626.
Record the quotient 9 as the next digit in the result. 
Result so far: 100059.939
If we take 5994 away from 6620, we end up with 626.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6260, and continue the process.

Moving on to step 12:
6260 divided by 666 is 9 with a remainder of 266.
Record the quotient 9 as the next digit in the result. 
Result so far: 100059.9399
If we take 5994 away from 6260, we end up with 266.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2660, and continue the process.

Our division results in 100059.9399 with a remaining 0.00266.