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: List one attribute that each of the following pairs of shapes have in common. There may be more than one correct answer.
a.   Square and rhombus
b.   Square and rectangle
c.   Square and parallelogram
d.   Square and trapezoid
e.   Square and quadrilateral


aligns: no