- This PDF File - The mathematics curriculum for Second Grade school students in the United States is designed to build a strong foundation in basic mathematical concepts and skills. *** Second Grade Unit 1 : Number Sense and Place Value *** - Understand place value for three-digit numbers (hundreds, tens, ones). - Count, read, and write numbers up to 1,000. This is everything you need to print and go to teach these concepts to a variety of learners - it will save you so much time! Plus, ALL of