Why does the earth spin? How is a rainbow formed? Feed the flame of curiosity in your child, and find out the answers to some of those age-old questions about how the world works.

Your child may be able to read a clock, but what about the passage of time? This workbook is all about elapsed time, and how to both estimate and calculate how much time has passed in between hours.

How well do you know words? Have fun with your English skills in this charming packet!

It's fact vs. opinion statements about interesting animals in this workbook. Kids will also think about how diagrams and images help clarify reading passages.

Let your voice be heard! This workbook challenges kids to express their opinions. But more importantly, they'll learn how to support opinions with good evidence and facts.

Learn presidential history, the functions of government and how elections work while having a blast. Read, write, color, cut and paste the way to knowledge of the past and present!

This workbook will challenge your fourth grader with math formulas, shapes practice and angle activities. Kids will also learn how to find areas and perimeters, classify triangles and calculate time.

Math is part of everyday life, so learn math concepts with everyday examples. Learn to calculate sales tax, discounts, income, expenses and how to get more bang for your buck!

Count and convert measurements for liquids, lengths and time with this supplemental book! So many practical skills come from knowing how to measure lengths, tell time and convert units of measurement.

Things are jumbled up at the newspaper! Your child has the know-how with the help of this workbook to set things right. Review grammar rules and practice composition through reading passages.

What's a metaphor? How do you haiku? Kids will hone reading and writing skills with this book, from a simple syllable counting exercise to inventing rhymes and tangling with the Jabberwocky!

Personal narrative writing is all about you—the writer! Kids will enjoy writing about themselves, from personal experiences and to feelings and emotions. Plus, they'll learn how to map a story.

Did you know that light can bend? Help your curious kids learn the important physical properties of light and explore how light adds colors to our world, with this beautiful series on light and color.

Get your kid on her way to mastering base 10 with this workbook. With an emphasis on place value, base 10 makes it easy for her to visualize large numbers and see how numbers relate to each other.

When Olympic swimmer Michael Phelps won a race by .01 of a second, we saw how significant a hundredth of a second can be! This series offers practice with decimals to build a solid understanding of the place value system.