One lesson that Ava learns that will help her life is that knowing the future and answers would never help her life which means, knowing everything can hurt somebody's emotion or feelings. For example, Ava asks some negative questions that is relating with her family to the pencil and the pencil replies her questions, the answers made Ava frustrated and thwart, and she realizes that the pencil is causing a lot of problem. So, this means to Ava is that knowing unrevealed things and answers would not make a victorious life for her, which this made Ava pessimistic at first. And also, she realizes her life is so much better with out her extraordinary blue pencil. Consequently, knowing everything and problems would never make a triumphant life for a person.
I'd rate this book an "8 out of 10." I would recommend this book because Ava is truthful and honest how she expresses her true emotions, and since the setting of this story is mostly school themed, it relates with students' life. One question that I'd ask to Ava is "How does a pencil affect and change your afterward life?"