standard_description: Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown number, or, depending on the purpose at hand, any number in a specified set.
problem_activity: Simplify the following expressions:
a.
$$(2^5)^7$$
b.
$$(91^3\times 19\times 103^8)^4$$
c.
$$(p^4q^5r)^9$$
d.
$$2^7\over 3^7$$


aligns: no