78398571 divided by 80 
We're looking to find how many times 80 goes into 78398571.

Moving on to step 1:
80 can be fit into 7 0 times, resulting in a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 7 and we're left with 7.
Grab the next digit (8) from the dividend, add it to 7, then carry on: 78 / 80

On to step 2:
If we divide 78 by 80, we get 0 and a remainder of 78.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 78 and we're left with 78.
Bring next digit (3) of the dividend behind the 78 and repeat the process: 783 / 80

Advancing to step 3:
783 divided by 80 is 9 with a remainder of 63.
The number 9 becomes the next digit in our result. 
Result so far: 9.0
Deduct 720 from 783 and we're left with 63.
Include the next digit (9) from the dividend after 63, then repeat: 639 / 80

Moving on to step 4:
When dividing 639 by 80, we get 7 with a remainder of 79.
Put 7 as the next digit of the answer. 
Result so far: 97.0
Subtract 560 from 639 to get 79.
Append the next digit (8) from the dividend to 79 and continue with: 798 / 80

Advancing to step 5:
If we divide 798 by 80, we get 9 and a remainder of 78.
Use 9 as the next digit of our solution. 
Result so far: 979.0
Subtract 720 from 798 to get 78.
Include the next digit (5) from the dividend after 78, then repeat: 785 / 80

Step 6:
785 divided by 80 is 9 with a remainder of 65.
The next digit of our result is 9. 
Result so far: 9799.0
If we subtract 720 from 785, we get 65.
Fetch the next digit (7) from the dividend, attach it to 65 and continue: 657 / 80

Let's proceed to step 7:
The number 80 fits into 657 8 times, leaving a remainder of 17.
Use 8 as the next digit of our solution. 
Result so far: 97998.0
If we subtract 640 from 657, we get 17.
Append the next digit (1) from the dividend to 17 and continue with: 171 / 80

Advancing to step 8:
The number 80 fits into 171 2 times, leaving a remainder of 11.
Record the quotient 2 as the next digit in the result. 
Result so far: 979982.0
Subtract 160 from 171 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 9:
When dividing 110 by 80, we get 1 with a remainder of 30.
Put 1 as the next digit of the answer. 
Result so far: 979982.1
The remainder is 30 after subtracting 80 from 110.
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 10:
300 divided by 80 is 3 with a remainder of 60.
Record the quotient 3 as the next digit in the result. 
Result so far: 979982.13
Deduct 240 from 300 and we're left with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Moving on to step 11:
The number 80 fits into 600 7 times, leaving a remainder of 40.
The number 7 becomes the next digit in our result. 
Result so far: 979982.137
Subtract 560 from 600 to get 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 12:
If we divide 400 by 80, we get 5 and a remainder of 0.
Write down 5 as next digit of the result. 
Result so far: 979982.1375
Subtracting 400 from 400 leaves us 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.

Advancing to step 13:
80 can be fit into 0 0 times, resulting in a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 979982.1375
Subtracting 0 from 0 leaves us 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.

Going ahead to step 14:
When dividing 0 by 80, we get 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 979982.1375
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final outcome is 979982.1375, with a leftover of 0.0.