We're dividing 126231 by 51 
We're looking to find how many times 51 goes into 126231.

Advancing to step 1:
51 can be fit into 1 0 times, resulting in a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Take the next digit (2) from the dividend and append it to 1, then repeat: 12 / 51

Advancing to step 2:
51 can be fit into 12 0 times, resulting in a remainder of 12.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 12 after subtracting 0 from 12.
Grab the next digit (6) from the dividend, add it to 12, then carry on: 126 / 51

Going ahead to step 3:
The number 51 fits into 126 2 times, leaving a remainder of 24.
The next digit of our result is 2. 
Result so far: 2.0
Subtract 102 from 126 to get 24.
Append the next digit (2) from the dividend to 24 and continue with: 242 / 51

Going ahead to step 4:
The number 51 fits into 242 4 times, leaving a remainder of 38.
The next digit of our result is 4. 
Result so far: 24.0
Subtract 204 from 242 to get 38.
Take the next digit (3) from the dividend and append it to 38, then repeat: 383 / 51

Going ahead to step 5:
383 divided by 51 is 7 with a remainder of 26.
The next digit of our result is 7. 
Result so far: 247.0
If we take 357 away from 383, we end up with 26.
Append the next digit (1) from the dividend to 26 and continue with: 261 / 51

Step 6:
If we divide 261 by 51, we get 5 and a remainder of 6.
Use 5 as the next digit of our solution. 
Result so far: 2475.0
Deduct 255 from 261 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Going ahead to step 7:
60 divided by 51 is 1 with a remainder of 9.
The next digit of our result is 1. 
Result so far: 2475.1
Deduct 51 from 60 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 8:
When dividing 90 by 51, we get 1 with a remainder of 39.
Write down 1 as next digit of the result. 
Result so far: 2475.11
Deduct 51 from 90 and we're left 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.

The final outcome is 2475.11, with a leftover of 0.039.