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
Find the value of each of the following.
a.
$${{1\over4}}$$
of
$${{12}}$$
b.
$${{3\over4}}$$
of
$${{12}}$$
Problem 2
There are 21 students in the chess club.
$$2\over3$$
of them are girls. How many girls are in the chess club?


aligns: no