National Council for Teachers of Mathematics Curriculum Standards STANDARD 2: MATHEMATICS AS COMMUNICATION In grades 5-8, the study of mathematics should include opportunities to communicated so that students can- model situations using oral, written, concrete, pictorial, graphical, and algebraic methods; reflect on and clarify their own thinking about mathematical ideas and situations; develop common understandings of mathematical ideas, including the role of definitions; use the skills of reading, listening, and viewing to interpret and evaluate mathematical ideas; discuss mathematical ideas and make conjectures and convincing arguments; appreciate the value of mathematical notation and its role in the development of mathematical ideas. STANDARD 9: GEOMETRY AND SPATIAL SENSE In grades K-4, the mathematics curriculum should include two- and three-dimensional geometry so that students can-- describe, model, draw, and classify shapes; investigate and predict the results of combining, subdividing, and changing shapes; develop spatial sense; relate geometric ideas to number and measurement ideas; recognize and appreciate geometry in their world. STANDARD 10: MEASUREMENT In grades K-4, the mathematics curriculum should include measurement so that students can- understand the attributes of length, circumference, and area; develop the process of measuring and concepts related to units of measurement; make and use measurements in problem and every day situations. STANDARD 13: MEASUREMENT In grades 5-8, the mathematics curriculum should include measurement so that students can- extend their understanding of the process of measurement; estimate, make, and use measurements to describe and compare phenomena; select appropriate units and tools to measure to the degree of accuracy required in a particular situation; understand the structure and use of systems of measurement; extend their understanding of the concepts of perimeter, area, volume, angle measure, capacity, and weight and mass; develop the concepts of rates and other derived and indirect measurements; develop formulas and procedures for determining measures to solve problems.