standard_description: Write, read, and evaluate expressions in which letters stand for numbers.
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