standard_description: Understand that rational expressions form a system analogous to the rational numbers, closed under addition, subtraction, multiplication, and division by a nonzero rational expression; add, subtract, multiply, and divide rational expressions.
problem_activity: Task
Use <, =,  or > to compare the following sums:
$\frac12 + \frac14$  ________  $\frac13 + \frac15$
$\frac13 + \frac12$  ________  $\frac13 + \frac14$


aligns: no