think! Mathematics Student Textbook 2A (Sold in Packs of 10)Numbers and Operations to 1,000 Students significantly expand their number sense through: Counting by ones, tens, and hundreds to 1,000 Comparing and ordering three digit numbers Discovering and creating number patterns Developing mental math strategies Understanding place value with hundreds, tens, and ones Advanced Addition and Subtraction Building on previous skills, students master: Addition and subtraction within 100 Mental math strategies for