505209 ÷ 12 
We want to divide 505209 by 12.

Advancing to step 1:
12 can be fit into 5 0 times, resulting in a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 5 and we're left with 5.
Take the next digit (0) from the dividend and append it to 5, then repeat: 50 / 12

Step 2:
12 can be fit into 50 4 times, resulting in a remainder of 2.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
Subtracting 48 from 50 leaves us with 2.
Grab the next digit (5) from the dividend, add it to 2, then carry on: 25 / 12

On to step 3:
25 divided by 12 is 2 with a remainder of 1.
Write down 2 as next digit of the result. 
Result so far: 42.0
Deduct 24 from 25 and we're left with 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 12

Step 4:
The number 12 fits into 12 1 times, leaving a remainder of 0.
Record the quotient 1 as the next digit in the result. 
Result so far: 421.0
If we take 12 away from 12, we end up with 0.
Take the next digit (0) from the dividend and append it to 0, then repeat: 0 / 12

On to step 5:
12 goes into 0 0 times with a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 4210.0
The remainder is 0 after subtracting 0 from 0.
Take the next digit (9) from the dividend and append it to 0, then repeat: 9 / 12

Going ahead to step 6:
If we divide 9 by 12, we get 0 and a remainder of 9.
The number 0 becomes the next digit in our result. 
Result so far: 42100.0
The remainder is 9 after subtracting 0 from 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Step 7:
12 goes into 90 7 times with a remainder of 6.
The next digit of our result is 7. 
Result so far: 42100.7
Deduct 84 from 90 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.

On to step 8:
12 goes into 60 5 times with a remainder of 0.
Write down 5 as next digit of the result. 
Result so far: 42100.75
Deduct 60 from 60 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 9:
If we divide 0 by 12, we get 0 and a remainder of 0.
The next digit of our result is 0. 
Result so far: 42100.75
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 10:
The number 12 fits into 0 0 times, leaving a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 42100.75
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The quotient of the division is 42100.75, and the remainder is 0.0.