Hiya D.A.,
I liked the idea of three friends accomplishing a task and finding themselves back in dinosaur days, or wherever they are. The main thing that stood out for me were the breaks in dialogue.
Take the first paragraph for instance:
QUOTE
Jimmy sat in his room. John sat in a chair on the other end of the room. On his lap sat a book and on the book sat a piece of paper. In his hand he held a pen. “Have you finished the equations,” asked Jimmy? “Not yet,” said John.
From what I understand, very rarely do you want to include dialogue by different people in the same paragraph. So you could perhaps change that paragraph to be:
QUOTE
. . . In his hand he held a pen. "Have you finished the equations?" asked Jimmy.
"Not yet," said John.
I also moved the "?" mark back into the quotes where it belongs since that is where the question occurs.
This type of thing happens a few more times through the piece. And for starters, I would recommend taking care of those first.
Overall, it has a lot of potential for filling in how this all came about, etc.
P.S. Those A+ certs can come in handy!