81990080 ÷ 661 
Our goal is to divide 81990080 by 661.

On to step 1:
When dividing 8 by 661, we get 0 with a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Grab the next digit (1) from the dividend, add it to 8, then carry on: 81 / 661

Advancing to step 2:
When dividing 81 by 661, we get 0 with a remainder of 81.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 81, we get 81.
Include the next digit (9) from the dividend after 81, then repeat: 819 / 661

Step 3:
661 goes into 819 1 times with a remainder of 158.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Deduct 661 from 819 and we're left with 158.
Include the next digit (9) from the dividend after 158, then repeat: 1589 / 661

Step 4:
When dividing 1589 by 661, we get 2 with a remainder of 267.
Use 2 as the next digit of our solution. 
Result so far: 12.0
The remainder is 267 after subtracting 1322 from 1589.
Include the next digit (0) from the dividend after 267, then repeat: 2670 / 661

On to step 5:
661 can be fit into 2670 4 times, resulting in a remainder of 26.
Record the quotient 4 as the next digit in the result. 
Result so far: 124.0
Subtracting 2644 from 2670 leaves us with 26.
Include the next digit (0) from the dividend after 26, then repeat: 260 / 661

Moving on to step 6:
260 divided by 661 is 0 with a remainder of 260.
Write down 0 as next digit of the result. 
Result so far: 1240.0
Deduct 0 from 260 and we're left with 260.
Bring next digit (8) of the dividend behind the 260 and repeat the process: 2608 / 661

Step 7:
2608 divided by 661 is 3 with a remainder of 625.
Use 3 as the next digit of our solution. 
Result so far: 12403.0
Deduct 1983 from 2608 and we're left with 625.
Append the next digit (0) from the dividend to 625 and continue with: 6250 / 661

Step 8:
6250 divided by 661 is 9 with a remainder of 301.
Write down 9 as next digit of the result. 
Result so far: 124039.0
Subtract 5949 from 6250 to get 301.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3010, and continue the process.

Advancing to step 9:
If we divide 3010 by 661, we get 4 and a remainder of 366.
The next digit of our result is 4. 
Result so far: 124039.4
The remainder is 366 after subtracting 2644 from 3010.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3660, and continue the process.

Let's proceed to step 10:
3660 divided by 661 is 5 with a remainder of 355.
Record the quotient 5 as the next digit in the result. 
Result so far: 124039.45
Subtracting 3305 from 3660 leaves us with 355.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3550, and continue the process.

Let's proceed to step 11:
661 goes into 3550 5 times with a remainder of 245.
Record the quotient 5 as the next digit in the result. 
Result so far: 124039.455
If we subtract 3305 from 3550, we get 245.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2450, and continue the process.

After the division, we end up with 124039.455 and a remainder of 0.0245.