Finding the Investment Gain for Retirement Planning

I am new to this, so I am not sure how to work this very well....



but I am working on a problem for an online class, and I have to find a variety of different items... I attached the file, I am not sure if it worked or not...

But the obvious column I'm looking for is the Investment Gain... and I can't figure out how to get it right.... the first couple answers are listed in the book, which is why I know my answers aren't coming out right. They first couple answers in the column are $104, $320, $658, $1127, $1737

If anyone can help I would appreciate it very much!