standard_description: Classify two-dimensional figures based on the presence or absence of parallel or perpendicular lines, or the presence or absence of angles of a specified size. Recognize right triangles as a category, and identify right triangles.
problem_activity: Problem 6
Pre-unit
Find the value of each expression.
\(206 + 543\)
\(327 + 181\)
\(674 - 129\)


aligns: no