In this book, children progress to two-digit addition while learning the commutative property of addition- an important foundation for future math success. Problems incorporate both horizontal and vertical form addition, which prepares children for practice with three and four-digit addition. Upon completion, your child will be ready for advanced arithmetic!Topics Covered in this Book:Horizontal addition reviewVertical form additionTwo-digit plus two-digit addition to 198Early three- & four-digit additionAddition of three two-digit numbersCommutative property of additionPatterns & sequencing