646880 ÷ 91 
Our goal is to divide 646880 by 91.

Moving on to step 1:
When dividing 6 by 91, we get 0 with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 91

Going ahead to step 2:
64 divided by 91 is 0 with a remainder of 64.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 64 leaves us with 64.
Fetch the next digit (6) from the dividend, attach it to 64 and continue: 646 / 91

Step 3:
If we divide 646 by 91, we get 7 and a remainder of 9.
Put 7 as the next digit of the answer. 
Result so far: 7.0
Deduct 637 from 646 and we're left with 9.
Append the next digit (8) from the dividend to 9 and continue with: 98 / 91

On to step 4:
When dividing 98 by 91, we get 1 with a remainder of 7.
Use 1 as the next digit of our solution. 
Result so far: 71.0
Deduct 91 from 98 and we're left with 7.
Fetch the next digit (8) from the dividend, attach it to 7 and continue: 78 / 91

Advancing to step 5:
The number 91 fits into 78 0 times, leaving a remainder of 78.
Record the quotient 0 as the next digit in the result. 
Result so far: 710.0
If we take 0 away from 78, we end up with 78.
Bring next digit (0) of the dividend behind the 78 and repeat the process: 780 / 91

On to step 6:
If we divide 780 by 91, we get 8 and a remainder of 52.
Put 8 as the next digit of the answer. 
Result so far: 7108.0
If we subtract 728 from 780, we get 52.
Since there are no more digits in the dividend, we add a zero to the remainder making it 520, and continue the process.

Advancing to step 7:
When dividing 520 by 91, we get 5 with a remainder of 65.
The number 5 becomes the next digit in our result. 
Result so far: 7108.5
Deduct 455 from 520 and we're left with 65.
Since there are no more digits in the dividend, we add a zero to the remainder making it 650, and continue the process.

Moving on to step 8:
650 divided by 91 is 7 with a remainder of 13.
The next digit of our result is 7. 
Result so far: 7108.57
Subtract 637 from 650 to get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Let's proceed to step 9:
130 divided by 91 is 1 with a remainder of 39.
Write down 1 as next digit of the result. 
Result so far: 7108.571
Subtracting 91 from 130 leaves us with 39.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

On to step 10:
91 can be fit into 390 4 times, resulting in a remainder of 26.
Write down 4 as next digit of the result. 
Result so far: 7108.5714
Subtracting 364 from 390 leaves us with 26.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

On to step 11:
The number 91 fits into 260 2 times, leaving a remainder of 78.
Put 2 as the next digit of the answer. 
Result so far: 7108.57142
If we take 182 away from 260, we end up with 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Step 12:
The number 91 fits into 780 8 times, leaving a remainder of 52.
The next digit of our result is 8. 
Result so far: 7108.571428
If we take 728 away from 780, we end up with 52.
Since there are no more digits in the dividend, we add a zero to the remainder making it 520, and continue the process.

Going ahead to step 13:
91 can be fit into 520 5 times, resulting in a remainder of 65.
The number 5 becomes the next digit in our result. 
Result so far: 7108.5714285
Deduct 455 from 520 and we're left with 65.
Since there are no more digits in the dividend, we add a zero to the remainder making it 650, and continue the process.

Moving on to step 14:
91 goes into 650 7 times with a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 7108.57142857
If we subtract 637 from 650, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

The final outcome is 7108.57142857, with a leftover of 1.3e-08.