The TI series of scientific calculators might be most popular for its graphing models, which can be programmed to perform any number of complex operations. But the TI-30XIIS is especially useful for high school level math and science for a couple of reasons. First, it's approved for use on the SAT, ACT and AP exams, so you can keep using the calculator you're used to during very important tests; and second, because it isn't quite as complex as other TI models, you can access operations like exponents straight from the keypad, without having to punch in a series of keys.
TL;DR (Too Long; Didn't Read)
Enter the base number, and then press the carat or ^ symbol (located along the left edge of the keyboard), followed by the exponent.
Enter the Base
Enter the base number for your exponent. For example, if the exponential expression in question is 53, the base number is 5.
Activate the Exponent Function
Press the carat or ^ symbol, which is located along the left edge of your calculator's keypad, about halfway between top and bottom.
Enter the Exponent
Enter the exponent; to continue with the previous example, in the exponential expression 53, the exponent is 3.
Complete the Operation
Press Enter, and the calculator will return the value of the exponent you just entered.