One of a select group of profs whose dedication shines through in every lecture, who has that special knack of simple and effective answers to course-related material.
Practice daily for best results. Daily work makes you smarter and leads you to success!

## Exercise of the Day:

Simplify $\left [ \left ( a + b \right )^{-1} + \left ( a + c \right )^{-1} + \left ( b + c \right )^{-1} \right ]^{-1}$.
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## Problem of the Day:

The digits $123456789$ can be arranged to form $362,880$ distinct $9$-digit numbers. How many of these are prime?
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