We look at the division of 666189 by 7 
The aim is to understand the frequency of 7 in 666189.

Step 1:
7 goes into 6 0 times with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Include the next digit (6) from the dividend after 6, then repeat: 66 / 7

Moving on to step 2:
When dividing 66 by 7, we get 9 with a remainder of 3.
The number 9 becomes the next digit in our result. 
Result so far: 9.0
Subtract 63 from 66 to get 3.
Take the next digit (6) from the dividend and append it to 3, then repeat: 36 / 7

On to step 3:
When dividing 36 by 7, we get 5 with a remainder of 1.
Use 5 as the next digit of our solution. 
Result so far: 95.0
Deduct 35 from 36 and we're left with 1.
Bring next digit (1) of the dividend behind the 1 and repeat the process: 11 / 7

Going ahead to step 4:
11 divided by 7 is 1 with a remainder of 4.
Put 1 as the next digit of the answer. 
Result so far: 951.0
The remainder is 4 after subtracting 7 from 11.
Append the next digit (8) from the dividend to 4 and continue with: 48 / 7

Step 5:
If we divide 48 by 7, we get 6 and a remainder of 6.
Record the quotient 6 as the next digit in the result. 
Result so far: 9516.0
If we subtract 42 from 48, we get 6.
Append the next digit (9) from the dividend to 6 and continue with: 69 / 7

Advancing to step 6:
7 goes into 69 9 times with a remainder of 6.
The next digit of our result is 9. 
Result so far: 95169.0
The remainder is 6 after subtracting 63 from 69.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 7:
7 goes into 60 8 times with a remainder of 4.
Record the quotient 8 as the next digit in the result. 
Result so far: 95169.8
Subtracting 56 from 60 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 8:
7 goes into 40 5 times with a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 95169.85
Deduct 35 from 40 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Advancing to step 9:
7 can be fit into 50 7 times, resulting in a remainder of 1.
Put 7 as the next digit of the answer. 
Result so far: 95169.857
If we subtract 49 from 50, we 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 10:
If we divide 10 by 7, we get 1 and a remainder of 3.
The next digit of our result is 1. 
Result so far: 95169.8571
If we take 7 away from 10, we end up with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 11:
7 goes into 30 4 times with a remainder of 2.
The next digit of our result is 4. 
Result so far: 95169.85714
If we subtract 28 from 30, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Let's proceed to step 12:
If we divide 20 by 7, we get 2 and a remainder of 6.
Use 2 as the next digit of our solution. 
Result so far: 95169.857142
Subtracting 14 from 20 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 13:
60 divided by 7 is 8 with a remainder of 4.
The next digit of our result is 8. 
Result so far: 95169.8571428
If we take 56 away from 60, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 14:
When dividing 40 by 7, we get 5 with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 95169.85714285
If we subtract 35 from 40, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Our division results in 95169.85714285 with a remaining 5e-09.