Dawn McMillan 
It Started with Pizza [PDF ebook] 

A family wants to share a pizza, but who gets how much? With this book, you’ll learn how mathematical equations can help you answer any mathematical questions. Apply equations to food measurements, the human body, and even outer space! With vibrant photos, math charts and diagrams, grade-appropriate text, and informational text features to help navigate the text, students will learn practical, real-world applications of math skills as they are introduced to variables, expressions, and equations, and build their STEM skills.