We're dividing 519121 by 12 
We want to figure out the number of times 519121 can be divided by 12.

Advancing to step 1:
12 goes into 5 0 times with a remainder of 5.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 5 and we're left with 5.
Append the next digit (1) from the dividend to 5 and continue with: 51 / 12

Advancing to step 2:
12 can be fit into 51 4 times, resulting in a remainder of 3.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
The remainder is 3 after subtracting 48 from 51.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 12

Advancing to step 3:
12 can be fit into 39 3 times, resulting in a remainder of 3.
The number 3 becomes the next digit in our result. 
Result so far: 43.0
If we subtract 36 from 39, we get 3.
Fetch the next digit (1) from the dividend, attach it to 3 and continue: 31 / 12

Moving on to step 4:
31 divided by 12 is 2 with a remainder of 7.
Write down 2 as next digit of the result. 
Result so far: 432.0
Deduct 24 from 31 and we're left with 7.
Fetch the next digit (2) from the dividend, attach it to 7 and continue: 72 / 12

Moving on to step 5:
The number 12 fits into 72 6 times, leaving a remainder of 0.
Write down 6 as next digit of the result. 
Result so far: 4326.0
If we subtract 72 from 72, we get 0.
Append the next digit (1) from the dividend to 0 and continue with: 1 / 12

Moving on to step 6:
When dividing 1 by 12, we get 0 with a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 43260.0
If we subtract 0 from 1, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

On to step 7:
12 can be fit into 10 0 times, resulting in a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 43260.0
If we take 0 away from 10, we end up 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 8:
100 divided by 12 is 8 with a remainder of 4.
The next digit of our result is 8. 
Result so far: 43260.08
Subtract 96 from 100 to get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 9:
If we divide 40 by 12, we get 3 and a remainder of 4.
Write down 3 as next digit of the result. 
Result so far: 43260.083
The remainder is 4 after subtracting 36 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 10:
When dividing 40 by 12, we get 3 with a remainder of 4.
Record the quotient 3 as the next digit in the result. 
Result so far: 43260.0833
The remainder is 4 after subtracting 36 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

In conclusion, the division gives 43260.0833 with a balance of 4e-05.