Polything wrote:
I don't know how to put an exponent to a number, such as 10 to the
power 24

Select the numbers of the exponent (in your example, 24), go to Format
Font, and select Superscript. The keyboard shortcut for this is Ctrl+Shift+=
(that is, the combination of Ctrl and Shift and the equal sign next to the
backspace key).

--
Regards,
Jay Freedman
Microsoft Word MVP FAQ: http://word.mvps.org