standard_description: Explain why the sum or product of two rational numbers is rational; that the sum of a rational number and an irrational number is irrational; and that the product of a nonzero rational number and an irrational number is irrational.
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