The Lab Gear books I wrote for Didax are the best books on how to use algebra manipulatives to teach a wide range of topics. (Where to get the books.) Unfortunately, they contain some errors, many of them minor. As I create corrected versions of those pages, I will post them here. If you find more errors, let me know!
If your books have "A B C D E 20 19 18 17 16" near the bottom of page ii, you have the first printing. Here are some corrected pages, which were fixed in the second printing. (See also below, for the pages that were missed in the second printing!)
Algebra Lab Gear: Basic Algebra
Algebra Lab Gear: Algebra 1
If your books have "A B C D E 20 19 18 17" near the bottom of page ii, you have the second printing. Here are some corrected pages, which were fixed in the third printing: