Description: Measure and estimate lengths in standard units. Second graders learn to measure length with a variety of tools, such as rulers, meter sticks, and measuring tapes (2.MD.A.1). Although this appears to some adults to be relatively simple, there are many conceptual and procedural issues to address. Area and volume: Foundations. To learn area (and, later, volume) concepts and skills meaningfully in later grades, students need to develop the ability known as spatial structuring. Students need to be able to see a rectangular region as decomposable into rows and columns of squares.