"Beta builds on the foundation in Alpha by applying students' mastery of single-digit addition and subtraction to multiple-digit addition and subtraction. One of the stepping stones between these two levels is the concept of place value, which is an important milestone for truly grasping any multiple-digit operation. Updates to the Instruction Manual include: suggestions for teaching odd and even numbers, suggestions for introducing centimeters and meters, as measurement units (no conversions) , information on am and pm with telling time, simple number line (in appendix)" -- publisher website.