Julia Vogel 
The Calendar [PDF ebook] 

A calendar can help people to count how long it is until their birthday. Calendars measure days, weeks, months, and years.
Learn about different types of calendars and the history of measuring days, weeks, months, and years in Calendar, an All About
Measuring book. Each book in this series helps children learn basic measuring concepts. Simple, engaging text and colorful
photos help students gain a better understanding of measurement fundamentals and encourage a love of reading.