This California college has a no-frills $612$$602$-page textbook available for free PDF download
available for free PDF download:
College of the Redwoods Mathematics Prealgebra Textbook. 2012-13. (weblinkPublisherLink).
A solutions manual is available at the same link. Because you canThere was a free website for download in 2015, but apparently no more. it easilyBefore its demise, you can browseI browsed through it to decide if it meets your needs before committing to your (admirable) projectbook.
What "fluff" the textbook authors include is hardly fluff; rather, educational:
![Horus][1]
Note the sum $$ \frac{1}{2} + \frac{1}{4} + \frac{1}{8} + \frac{1}{16} + \frac{1}{32} + \frac{1}{64} = \frac{63}{64} $$ is missing $\frac{1}{64}$ of Horus's eye.