Deluxe edition. Follows NCTM guidelines. An I Know It! book. Practicing addition and subtraction skills can be easy and fun with clear instructions, step-by-step examples, and colorful illustrations. Engaging activities teach and reinforce place values, regrouping, fact families, and more. Principles and Standards for School Mathematics, published by the National Council of Teachers of Mathematics (NCTM), was used as a guide in writing this book. Skills include: Place value; Regrouping; Two-digit addition & subtraction; Fact families; Using a number line; Three-digit addition & subtraction. Review, reinforce & accelerate learning! All School Zone products are developed by skilled educators to provide the highest quality, up-to-date curriculum possible. Workbooks: Top-quality content, clear directions, and full-color illustrations make School Zone workbooks the best choice. Made in the USA.