We look at the division of 12486155 by 661 
We're looking to find how many times 661 goes into 12486155.

Advancing to step 1:
1 divided by 661 is 0 with a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 661

Advancing to step 2:
12 divided by 661 is 0 with a remainder of 12.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 12, we get 12.
Take the next digit (4) from the dividend and append it to 12, then repeat: 124 / 661

Moving on to step 3:
The number 661 fits into 124 0 times, leaving a remainder of 124.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 124 and we're left with 124.
Append the next digit (8) from the dividend to 124 and continue with: 1248 / 661

Advancing to step 4:
If we divide 1248 by 661, we get 1 and a remainder of 587.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Deduct 661 from 1248 and we're left with 587.
Grab the next digit (6) from the dividend, add it to 587, then carry on: 5876 / 661

Advancing to step 5:
661 goes into 5876 8 times with a remainder of 588.
Write down 8 as next digit of the result. 
Result so far: 18.0
If we subtract 5288 from 5876, we get 588.
Bring next digit (1) of the dividend behind the 588 and repeat the process: 5881 / 661

Let's proceed to step 6:
661 can be fit into 5881 8 times, resulting in a remainder of 593.
Use 8 as the next digit of our solution. 
Result so far: 188.0
Subtracting 5288 from 5881 leaves us with 593.
Include the next digit (5) from the dividend after 593, then repeat: 5935 / 661

Moving on to step 7:
661 goes into 5935 8 times with a remainder of 647.
Record the quotient 8 as the next digit in the result. 
Result so far: 1888.0
The remainder is 647 after subtracting 5288 from 5935.
Include the next digit (5) from the dividend after 647, then repeat: 6475 / 661

Advancing to step 8:
6475 divided by 661 is 9 with a remainder of 526.
The next digit of our result is 9. 
Result so far: 18889.0
Subtract 5949 from 6475 to get 526.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5260, and continue the process.

Going ahead to step 9:
If we divide 5260 by 661, we get 7 and a remainder of 633.
Put 7 as the next digit of the answer. 
Result so far: 18889.7
The remainder is 633 after subtracting 4627 from 5260.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6330, and continue the process.

Step 10:
661 goes into 6330 9 times with a remainder of 381.
Put 9 as the next digit of the answer. 
Result so far: 18889.79
Subtract 5949 from 6330 to get 381.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3810, and continue the process.

Advancing to step 11:
If we divide 3810 by 661, we get 5 and a remainder of 505.
Put 5 as the next digit of the answer. 
Result so far: 18889.795
Subtract 3305 from 3810 to get 505.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5050, and continue the process.

Advancing to step 12:
If we divide 5050 by 661, we get 7 and a remainder of 423.
Use 7 as the next digit of our solution. 
Result so far: 18889.7957
If we subtract 4627 from 5050, we get 423.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4230, and continue the process.

On to step 13:
The number 661 fits into 4230 6 times, leaving a remainder of 264.
The next digit of our result is 6. 
Result so far: 18889.79576
Deduct 3966 from 4230 and we're left with 264.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2640, and continue the process.

Going ahead to step 14:
If we divide 2640 by 661, we get 3 and a remainder of 657.
Use 3 as the next digit of our solution. 
Result so far: 18889.795763
Subtracting 1983 from 2640 leaves us with 657.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6570, and continue the process.

Let's proceed to step 15:
661 can be fit into 6570 9 times, resulting in a remainder of 621.
Record the quotient 9 as the next digit in the result. 
Result so far: 18889.7957639
Subtract 5949 from 6570 to get 621.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6210, and continue the process.

Going ahead to step 16:
661 can be fit into 6210 9 times, resulting in a remainder of 261.
Write down 9 as next digit of the result. 
Result so far: 18889.79576399
If we take 5949 away from 6210, we end up with 261.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2610, and continue the process.

The final outcome is 18889.79576399, with a leftover of 2.61e-07.