Powers How do you type in a problem such as..... 2.998 x 10^-18/5.874 x 10^8.

Use following sequence following exactly your problem

2.998
X
(
18
/
5.874
)
2nd, 10 to power x
X
8
10 to power x
=

When evaluating a "10 to the power x" expression, you first enter the exponent number, then press the "2nd, 10 to the power" key. Same as getting the value of "sin 60", first enter 60, then the "SIN" key.

The (18/5.874) sequence in the middle has to be in (.....) is because you first have to get the value of that expression (however complicated it is) before you tell the calculator you want to raise 10 to the power of the resultant number.