I don't think you have to be able to calculate this stuff at the table. But it helps to have a general sense of how the numbers work. If you think "I really really doubt you have that hand, it makes no sense at all" and then think "but does it make sense to call triple the pot?" -- then having just looked at these numbers a few times, the answer is yes, you should make that call.
You can also figure it the other way around.
"He just bet 9.5x the pot. Should I call?" The answer is: Only if I think he is beating me less than 5% of the time. Or, in other words, almost always -- nope, fold it.