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: Problem 1
Solve. Show or explain your work.
$${2{5\over8}+4{2\over3}}$$
Problem 2
Sang needs
$$3\tfrac{1}{2}$$
feet of string to make a necklace and
$$2\tfrac{1}{4}$$
feet of string left. How much string, in feet, did Sang have before making the necklace?


aligns: yes