5 books in series

Crowell Young Math Books

Crowell Young Math Books is a 5-book series with 5 primary works first released in 1975 with contributions by John V. Trivett, Giulio Maestro, Robert Froman, Byron Barton, Malcolm E. Weiss, Clyde Watson, Mindel Sitomer, and Harry Sitomer.

Binary Numbers
Building tables on tables
Zero is not nothing
Angles Are Easy As Pie
666 Jellybeans! All That?: An Introduction to Algebra