standard_description: Add and subtract fractions with unlike denominators (including mixed numbers) by replacing given fractions with equivalent fractions in such a way as to produce an equivalent sum or difference of fractions with like denominators. For example, 2/3 + 5/4 = 8/12 + 15/12 = 23/12. (In general, a/b + c/d = (ad + bc)/bd.)
problem_activity: Task
Decide whether each of these statements is always, sometimes, or never true.  If it is sometimes true, draw and describe a figure for which the statement is true and another figure for which the statement is not true.
A rhombus is a square
A triangle is a parallelogram
A square is a parallelogram
A square is a rhombus
A parallelogram is a rectangle
A trapezoid is a quadrilateral


aligns: no