Why do P→(Q→R) and (P→Q)→R have different truth tables?

[Mdhiggenz]

Homework Statement

Hello, I was working on the following truth table problems
1.P→(Q→R)
2.(P→Q)→R

and wanted to know why I got different truth tables it seems that we could use the associative law to rewrite 1. in the same manner as 2.

Or am I missing something?

Thanks

Higgenz

Homework Equations

The Attempt at a Solution

 

[HallsofIvy]

What "associative law" are you talking about? As far as I know there is no "associative law" for implications.

Here, these two statements are clearly not the same.