- This PDF File - The mathematics curriculum for Fourth Grade students in the United States is designed to build a strong foundation in basic mathematical concepts and skills. *** Fourth Grade Unit 4 : Properties of angles and lines - Understand properties of angles and lines. - Classify Angles and Lines by properties (e.g., parallel sides, right angles). 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 you