3Number Fill-Ins Brain Exercises.This book is filled with 100 Number Fill-Ins puzzles. These puzzles are suitable for all age. The goal is simple: fill a grid with the number from a list. Easy ? Yes, but solving this puzzle requires judgment, a keen eye and also a little bit of patience. Exactly what you need to cultivate to have a good mental shape. !This book has 100 puzzles printed in large print to stimulate your brain not to strain your eyes. Also each puzzle has a hint already written in the grid. You will be delighted by this book.