We look at the division of 669670 by 77 
The aim is to understand the frequency of 77 in 669670.

Step 1:
6 divided by 77 is 0 with a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Bring next digit (6) of the dividend behind the 6 and repeat the process: 66 / 77

Step 2:
77 goes into 66 0 times with 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.
Fetch the next digit (9) from the dividend, attach it to 66 and continue: 669 / 77

Let's proceed to step 3:
77 goes into 669 8 times with a remainder of 53.
The next digit of our result is 8. 
Result so far: 8.0
If we take 616 away from 669, we end up with 53.
Bring next digit (6) of the dividend behind the 53 and repeat the process: 536 / 77

Step 4:
The number 77 fits into 536 6 times, leaving a remainder of 74.
Write down 6 as next digit of the result. 
Result so far: 86.0
If we take 462 away from 536, we end up with 74.
Grab the next digit (7) from the dividend, add it to 74, then carry on: 747 / 77

Advancing to step 5:
When dividing 747 by 77, we get 9 with a remainder of 54.
The next digit of our result is 9. 
Result so far: 869.0
If we subtract 693 from 747, we get 54.
Include the next digit (0) from the dividend after 54, then repeat: 540 / 77

Let's proceed to step 6:
If we divide 540 by 77, we get 7 and a remainder of 1.
Write down 7 as next digit of the result. 
Result so far: 8697.0
Subtracting 539 from 540 leaves us with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Let's proceed to step 7:
The number 77 fits into 10 0 times, leaving a remainder of 10.
The next digit of our result is 0. 
Result so far: 8697.0
Deduct 0 from 10 and we're left with 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 8:
The number 77 fits into 100 1 times, leaving a remainder of 23.
The number 1 becomes the next digit in our result. 
Result so far: 8697.01
If we take 77 away from 100, we end up with 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

Moving on to step 9:
77 can be fit into 230 2 times, resulting in a remainder of 76.
Record the quotient 2 as the next digit in the result. 
Result so far: 8697.012
If we take 154 away from 230, we end up with 76.
Since there are no more digits in the dividend, we add a zero to the remainder making it 760, and continue the process.

Step 10:
If we divide 760 by 77, we get 9 and a remainder of 67.
Write down 9 as next digit of the result. 
Result so far: 8697.0129
The remainder is 67 after subtracting 693 from 760.
Since there are no more digits in the dividend, we add a zero to the remainder making it 670, and continue the process.

Advancing to step 11:
The number 77 fits into 670 8 times, leaving a remainder of 54.
Put 8 as the next digit of the answer. 
Result so far: 8697.01298
Subtract 616 from 670 to get 54.
Since there are no more digits in the dividend, we add a zero to the remainder making it 540, and continue the process.

On to step 12:
If we divide 540 by 77, we get 7 and a remainder of 1.
Record the quotient 7 as the next digit in the result. 
Result so far: 8697.012987
Deduct 539 from 540 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 13:
When dividing 10 by 77, we get 0 with a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 8697.012987
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.

Step 14:
77 goes into 100 1 times with a remainder of 23.
Use 1 as the next digit of our solution. 
Result so far: 8697.01298701
If we take 77 away from 100, we end up with 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

The final result is 8697.01298701 with a remainder of 2.3e-08.