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: Problem 1
Simplify
$${\sqrt{8}+5\sqrt{2}}$$
.
Problem 2
Write a radical addition or subtraction problem that cannot be simplified, and explain why it cannot be simplified.


aligns: no