We're dividing 518945 by 3 
Let's see how many times 3 fits into 518945.

On 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
Deduct 3 from 5 and we're left with 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 3

Going ahead to step 2:
21 divided by 3 is 7 with a remainder of 0.
The number 7 becomes the next digit in our result. 
Result so far: 17.0
If we subtract 21 from 21, we get 0.
Append the next digit (8) from the dividend to 0 and continue with: 8 / 3

Step 3:
8 divided by 3 is 2 with a remainder of 2.
Write down 2 as next digit of the result. 
Result so far: 172.0
If we take 6 away from 8, we end up with 2.
Grab the next digit (9) from the dividend, add it to 2, then carry on: 29 / 3

On to step 4:
When dividing 29 by 3, we get 9 with a remainder of 2.
Record the quotient 9 as the next digit in the result. 
Result so far: 1729.0
Subtract 27 from 29 to get 2.
Append the next digit (4) from the dividend to 2 and continue with: 24 / 3

On to step 5:
The number 3 fits into 24 8 times, leaving a remainder of 0.
Write down 8 as next digit of the result. 
Result so far: 17298.0
Subtract 24 from 24 to get 0.
Fetch the next digit (5) from the dividend, attach it to 0 and continue: 5 / 3

Advancing to step 6:
If we divide 5 by 3, we get 1 and a remainder of 2.
Use 1 as the next digit of our solution. 
Result so far: 172981.0
Subtract 3 from 5 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 7:
If we divide 20 by 3, we get 6 and a remainder of 2.
The number 6 becomes the next digit in our result. 
Result so far: 172981.6
Subtracting 18 from 20 leaves us with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Step 8:
The number 3 fits into 20 6 times, leaving a remainder of 2.
Record the quotient 6 as the next digit in the result. 
Result so far: 172981.66
The remainder is 2 after subtracting 18 from 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

The final result is 172981.66 with a remainder of 0.002.