We divide 503686 by 3
We want to figure out the number of times 503686 can be divided by 3.

Let's proceed to step 1:
3 goes into 5 1 times with a remainder of 2.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
The remainder is 2 after subtracting 3 from 5.
Fetch the next digit (0) from the dividend, attach it to 2 and continue: 20 / 3

Step 2:
20 divided by 3 is 6 with a remainder of 2.
Put 6 as the next digit of the answer. 
Result so far: 16.0
The remainder is 2 after subtracting 18 from 20.
Append the next digit (3) from the dividend to 2 and continue with: 23 / 3

Advancing to step 3:
3 goes into 23 7 times with a remainder of 2.
Record the quotient 7 as the next digit in the result. 
Result so far: 167.0
If we subtract 21 from 23, we get 2.
Include the next digit (6) from the dividend after 2, then repeat: 26 / 3

On to step 4:
When dividing 26 by 3, we get 8 with a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 1678.0
If we take 24 away from 26, we end up with 2.
Fetch the next digit (8) from the dividend, attach it to 2 and continue: 28 / 3

On to step 5:
3 goes into 28 9 times with a remainder of 1.
The next digit of our result is 9. 
Result so far: 16789.0
If we subtract 27 from 28, we get 1.
Bring next digit (6) of the dividend behind the 1 and repeat the process: 16 / 3

Moving on to step 6:
When dividing 16 by 3, we get 5 with a remainder of 1.
Write down 5 as next digit of the result. 
Result so far: 167895.0
Subtract 15 from 16 to 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.

Let's proceed to step 7:
3 can be fit into 10 3 times, resulting in a remainder of 1.
Put 3 as the next digit of the answer. 
Result so far: 167895.3
Subtract 9 from 10 to 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.

Step 8:
If we divide 10 by 3, we get 3 and a remainder of 1.
Put 3 as the next digit of the answer. 
Result so far: 167895.33
Deduct 9 from 10 and we're left 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.

The final result is 167895.33 with a remainder of 0.001.