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
Mrs. Fowler knew that the perimeter of the soccer field was
$${{1\over6}}$$
mile. She walked
$$2{{{1\over6}}}$$
miles in total. How many times did she walk around the field? Show or explain your work.
Problem 2
Convert the following mixed numbers to fractions greater than 1. Show or explain your work.
a.
$${3{1\over2}}$$
b.
$${4{1\over4}}$$
c.
$${5{3\over5}}$$
Problem 3
Ben wrote the mixed number
$$7\frac{1}{3}$$
as a fraction. Here is his work:
| $$7\frac{1}{3}= 7 + \frac{1}{3}$$ | (Step 1) |
|-----------------------------------|----------|
|   $$=\frac{7}{1}+\frac{1}{3}$$    | (Step 2) |
|   $$=\frac{21}{3}+\frac{1}{3}$$   | (Step 3) |
|         $${={22\over3}}$$         | (Step 4) |
Explain what Ben did in each step.


aligns: no