Let's divide 39978 by 77
The aim is to understand the frequency of 77 in 39978.

Step 1:
When dividing 3 by 77, we get 0 with a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 3 after subtracting 0 from 3.
Take the next digit (9) from the dividend and append it to 3, then repeat: 39 / 77

Advancing to step 2:
77 can be fit into 39 0 times, resulting in a remainder of 39.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 39, we get 39.
Include the next digit (9) from the dividend after 39, then repeat: 399 / 77

Going ahead to step 3:
77 goes into 399 5 times with a remainder of 14.
Put 5 as the next digit of the answer. 
Result so far: 5.0
Deduct 385 from 399 and we're left with 14.
Bring next digit (7) of the dividend behind the 14 and repeat the process: 147 / 77

On to step 4:
77 can be fit into 147 1 times, resulting in a remainder of 70.
Write down 1 as next digit of the result. 
Result so far: 51.0
Deduct 77 from 147 and we're left with 70.
Include the next digit (8) from the dividend after 70, then repeat: 708 / 77

Going ahead to step 5:
If we divide 708 by 77, we get 9 and a remainder of 15.
The number 9 becomes the next digit in our result. 
Result so far: 519.0
Subtracting 693 from 708 leaves us with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Advancing to step 6:
77 can be fit into 150 1 times, resulting in a remainder of 73.
Write down 1 as next digit of the result. 
Result so far: 519.1
If we take 77 away from 150, we end up with 73.
Since there are no more digits in the dividend, we add a zero to the remainder making it 730, and continue the process.

Moving on to step 7:
The number 77 fits into 730 9 times, leaving a remainder of 37.
Use 9 as the next digit of our solution. 
Result so far: 519.19
If we take 693 away from 730, we end up with 37.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

Going ahead to step 8:
The number 77 fits into 370 4 times, leaving a remainder of 62.
Record the quotient 4 as the next digit in the result. 
Result so far: 519.194
Subtract 308 from 370 to get 62.
Since there are no more digits in the dividend, we add a zero to the remainder making it 620, and continue the process.

Moving on to step 9:
77 goes into 620 8 times with a remainder of 4.
Record the quotient 8 as the next digit in the result. 
Result so far: 519.1948
Subtract 616 from 620 to get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 10:
40 divided by 77 is 0 with a remainder of 40.
Record the quotient 0 as the next digit in the result. 
Result so far: 519.1948
The remainder is 40 after subtracting 0 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Let's proceed to step 11:
The number 77 fits into 400 5 times, leaving a remainder of 15.
The next digit of our result is 5. 
Result so far: 519.194805
If we take 385 away from 400, we end up with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 12:
150 divided by 77 is 1 with a remainder of 73.
Record the quotient 1 as the next digit in the result. 
Result so far: 519.1948051
The remainder is 73 after subtracting 77 from 150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 730, and continue the process.

On to step 13:
730 divided by 77 is 9 with a remainder of 37.
The number 9 becomes the next digit in our result. 
Result so far: 519.19480519
Deduct 693 from 730 and we're left with 37.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

After the division, we end up with 519.19480519 and a remainder of 3.7e-08.