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: Solve. Show or explain your work.
a.
$${{2\over3} \times {5\over6}}$$
b.
$${{4\over9} \times { 3\over 8}}$$


aligns: no