This book falls into the readiness category if you consider knowing letters and sounds plus numbers and counting up to 20 as pre-kindergarten skills. A Beka uses this book as part of their K-4 or early kindergarten program. However, some might use it earlier or later, depending upon the child. You should be using A Beka's Phonics/Reading/Writing Curriculum/Lesson Plans to understand their method of presenting phonics (consonant-vowel pairs on ladders); ABC-123 is not designed to be used alone.
Children learn to write letters and numbers, but they do not write whole words in this book. Most exercises require circling correct answers and connecting lines between items.