Carson Dellosa Education 
Spectrum Place Value and Rounding [PDF ebook] 

Math understanding will fall into place when kids use Spectrum Focus: Place Value and Rounding for grade 3-it provides extensive practice to help children regroup, estimate, round, add, and subtract multi-digit numbers. Packed with introductions, explanations, and comprehensive assessments, the Spectrum Focus series is designed to help every child meet (and exceed) expectations by offering an in-depth learning experience. This standards-based workbook doesn’t just prepare them for classroom success-it helps them make real-world connections by applying learned skills to everyday scenarios.