215 books • 12 series
Numbricks For Kids 150 Very Easy to Easy Numbricks 8x8 (Numbricks Puzzle Books for Kids, #24)
Numbricks For Kids 150 Very Easy to Easy Numbricks 5x5 (Numbricks Puzzle Books for Kids, #9)
Numbricks For Kids 150 Easy to Medium Numbricks 4x4 (Numbricks Puzzle Books for Kids, #5)