878139 divided by 80 
The aim is to understand the frequency of 80 in 878139.

On to step 1:
If we divide 8 by 80, we get 0 and a remainder of 8.
The next digit of our result is 0. 
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 / 80

Let's proceed to step 2:
When dividing 87 by 80, we get 1 with a remainder of 7.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
The remainder is 7 after subtracting 80 from 87.
Fetch the next digit (8) from the dividend, attach it to 7 and continue: 78 / 80

On to step 3:
80 can be fit into 78 0 times, resulting in a remainder of 78.
Write down 0 as next digit of the result. 
Result so far: 10.0
The remainder is 78 after subtracting 0 from 78.
Fetch the next digit (1) from the dividend, attach it to 78 and continue: 781 / 80

Advancing to step 4:
When dividing 781 by 80, we get 9 with a remainder of 61.
The next digit of our result is 9. 
Result so far: 109.0
Subtracting 720 from 781 leaves us with 61.
Grab the next digit (3) from the dividend, add it to 61, then carry on: 613 / 80

Advancing to step 5:
When dividing 613 by 80, we get 7 with a remainder of 53.
The next digit of our result is 7. 
Result so far: 1097.0
Subtract 560 from 613 to get 53.
Fetch the next digit (9) from the dividend, attach it to 53 and continue: 539 / 80

Let's proceed to step 6:
When dividing 539 by 80, we get 6 with a remainder of 59.
Write down 6 as next digit of the result. 
Result so far: 10976.0
Subtracting 480 from 539 leaves us with 59.
Since there are no more digits in the dividend, we add a zero to the remainder making it 590, and continue the process.

On to step 7:
The number 80 fits into 590 7 times, leaving a remainder of 30.
The number 7 becomes the next digit in our result. 
Result so far: 10976.7
The remainder is 30 after subtracting 560 from 590.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Moving on to step 8:
If we divide 300 by 80, we get 3 and a remainder of 60.
Write down 3 as next digit of the result. 
Result so far: 10976.73
The remainder is 60 after subtracting 240 from 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

On to step 9:
The number 80 fits into 600 7 times, leaving a remainder of 40.
Write down 7 as next digit of the result. 
Result so far: 10976.737
Subtracting 560 from 600 leaves us with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Step 10:
80 can be fit into 400 5 times, resulting in a remainder of 0.
Put 5 as the next digit of the answer. 
Result so far: 10976.7375
Deduct 400 from 400 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 11:
0 divided by 80 is 0 with a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 10976.7375
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 12:
0 divided by 80 is 0 with a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 10976.7375
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Our division results in 10976.7375 with a remaining 0.0.