18991 divided by 51 
Our goal is to divide 18991 by 51.

On to step 1:
51 goes into 1 0 times with a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 1 and we're left with 1.
Grab the next digit (8) from the dividend, add it to 1, then carry on: 18 / 51

Advancing to step 2:
If we divide 18 by 51, we get 0 and a remainder of 18.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 18 leaves us with 18.
Fetch the next digit (9) from the dividend, attach it to 18 and continue: 189 / 51

Advancing to step 3:
If we divide 189 by 51, we get 3 and a remainder of 36.
Put 3 as the next digit of the answer. 
Result so far: 3.0
If we take 153 away from 189, we end up with 36.
Take the next digit (9) from the dividend and append it to 36, then repeat: 369 / 51

Going ahead to step 4:
51 can be fit into 369 7 times, resulting in a remainder of 12.
Use 7 as the next digit of our solution. 
Result so far: 37.0
If we subtract 357 from 369, we get 12.
Bring next digit (1) of the dividend behind the 12 and repeat the process: 121 / 51

Going ahead to step 5:
The number 51 fits into 121 2 times, leaving a remainder of 19.
Put 2 as the next digit of the answer. 
Result so far: 372.0
Subtracting 102 from 121 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

On to step 6:
51 goes into 190 3 times with a remainder of 37.
Use 3 as the next digit of our solution. 
Result so far: 372.3
Deduct 153 from 190 and we're left with 37.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

Going ahead to step 7:
The number 51 fits into 370 7 times, leaving a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 372.37
Subtracting 357 from 370 leaves us with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 8:
51 can be fit into 130 2 times, resulting in a remainder of 28.
Write down 2 as next digit of the result. 
Result so far: 372.372
Subtracting 102 from 130 leaves us with 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Step 9:
If we divide 280 by 51, we get 5 and a remainder of 25.
The number 5 becomes the next digit in our result. 
Result so far: 372.3725
Subtracting 255 from 280 leaves us with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

On to step 10:
The number 51 fits into 250 4 times, leaving a remainder of 46.
The next digit of our result is 4. 
Result so far: 372.37254
Deduct 204 from 250 and we're left with 46.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

Step 11:
51 goes into 460 9 times with a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 372.372549
If we take 459 away from 460, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 12:
The number 51 fits into 10 0 times, leaving a remainder of 10.
The next digit of our result is 0. 
Result so far: 372.372549
Deduct 0 from 10 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Moving on to step 13:
51 can be fit into 100 1 times, resulting in a remainder of 49.
Put 1 as the next digit of the answer. 
Result so far: 372.37254901
Subtract 51 from 100 to get 49.
Since there are no more digits in the dividend, we add a zero to the remainder making it 490, and continue the process.

The final outcome is 372.37254901, with a leftover of 4.9e-08.