pcat math

This might be a really dumb question but is there an EXP (exponent) button on the calculator provided in the PCAT? I don't understand how I can complete questions like the amount of energy emitted. How will I plug in -RH (-2.18x10^-18) on a standard calculator?

Hi guys, just wanted to ask what you guys would recommend i do to prepare for the math section of the exam. I have limited knowledge of pre calc/ calc because i took the classes 3-4 years ago and most of what i learned slipped my mind already. What is the best way to make sure to ace this...