In The Absolutely True Diary of a Part-Time Indian by Sherman Alexie, what does the old math book symbolize to Junior?

In the beginning of Sherman Alexie's book, The Absolutely True Diary of a Part-Time Indian, Junior lives and goes to school on the Spokane reservation. Like most things on "The Rez," Junior's school is quite poor and run-down. They cannot afford new textbooks on a regular basis, so students in Junior's class have to make do with books which are almost half a century old. Life on the reservation is persistently behind the times because First Nations people are not made a priority-- indeed, often fall to the end of the line-- in terms of infrastructure, resources, and economic development. Important things like health care and up-to-date textbooks just aren't made available on Junior's reservation because his people are stuck in a cycle of poverty.

At first, Junior is excited about the geometry book. But when he opens it and sees his mother's name on the inside cover, he realizes how poor and behind the times his school really is. He feels that the book is both a representation and manifestation of a  much larger trend that affects his culture: First Nations people aren't considered important enough to have new, working, good things in their lives. Junior almost equates his self worth with this old book and the system which prevents him from having anything better. (This is why he chooses to go to the "white school" in the next town over.) He is so mad, he throws the book in his teacher's face!