Answer :

It's closer to 1 because it is over half.
The easiest way to think about this is to give all of the numbers common denominators:
1 can be written as 6/6
0 can be written as 0/6

Now we can see that 5/6 is only 1/6 away from 1, while it is 5/6 away from 0.

So, 5/6 is closer to 1!