My kids always work simultaneously through two different math curricula. Right now, Peter is starting chapter 5 of AOPS pre-algebra and will be finishing up the Hands on Equations Word Problems book in the next few days. Both of these resources are providing him with a good level of challenge - not too easy, not too hard.
He will be continuing AOPS Pre-A, but I am trying to decide what new resource to start to replace HOE. I have on hand: Mathematics: A Human Endeavor, Zaccaro's Real World Algebra, and Math Mammoth Algebra. I am also open to other ideas.
Ideally, I am looking for something that will challenge him, get him thinking about math in new ways, and set the stage for him to thrive in AOPS Algebra when he gets there.
The MM Algebra is just practice worksheets, no instruction, but I could easily teach him the concepts, and I have no doubt that he would grasp them quickly. While I would certainly prefer something less teacher intensive (and more fun), it does seem to cover a lot material that he has never seen before like sets, graphing linear equations and factoring polynomials. These are all things I would like him to encounter before he gets to them in AOPS.
The Real World Algebra actually looks pretty easy, perhaps easier than the Hands on Equations word problems. We would probably only do the "Einstein Level" problems. I do like how it explicitly teaches problem solving techniques and shows lots of examples of how to properly write math solutions, but it doesn't really seem like it would be teaching him anything new.
I'm having a hard time getting a feel for the difficulty level of Mathematics: A Human Endeavor. Is algebra a pre-req? Glancing through I see graphing and factorials and sine curves, but like with MM, I could teach him necessary concepts as we came to them. I might have to tear out the title page with the subtitle "A Book for Those Who Think They Don't Like the Subject". Peter loves math, and I think he would be intrigued by some of the interesting applications explored in the book...but we could also hold off and use it simultaneously with AOPS algebra.
What do you think? Which would you use? Or is there something else I should look at?