Correct the errors.

Hello, Part of my assignment for this week in my class is to find the 20 errors in the below passage in each of the different listed aspects. I found 18, but cannot find the other two, can someone check and see if my answers are right and which two I am missing? Thank you.
The 20 errors are in the following categories: comma usage (six errors); question marks, apostrophes, and quotation marks (five errors); capitalization (six errors); and colons, semi-colons, and commonly misused words (three errors).
What I have found:
Comma - | | | | |
Question - |
Apostrophe - | |
Quotation - |
Caps - | | | | | |
Colons - |
Semicolons - |
Words - |
Passage:

Why are great numbers of students choosing to pursue their college degrees using their home computers. (?) Benjamin Franklin said;(said,) ("a) A penny saved is a penny earned". This principle applies to the american (American) and foreign online student. Todays (Today's) students choose to take online courses to save money on (previous to a list should be a colon - transportation, books, babysitters (babysitters,) and supplies.
The fluctuating cost of gasoline in the united states (United States) is one reason online courses appeal to axia college (Axia College) students. They would rather cushion there (their) financial nest eggs than to spend money on replacing worn tires or risking icy road conditions.
Students also realize that a traditional college requires them to purchase numerous books however, (,however, - separate the word "however" with two comma's not one) online courses provide the majority of their course materials within the virtual classroom. A student may save hundreds of dollars on textbooks during one block of courses.
Additionally online courses are convenient for parents and caregivers. (caregivers;) College (college) students who are responsible for children or aging parents must rely on outside help. An online student is able to avoid the high costs of hiring people to take care of their loved ones.

Lastly, an online student does not have to purchase supplies. Pencils, pens, paper, erasers, backpacks (backpacks,) staplers, and paper clips are all needed in traditional courses. The online student needs only one tool to complete their college degree; a home computer. A computer is an online students (student's) conduit to class(,) and to all the materials he or she needs.

Franklin D. roosevelt (Roosevelt) exclaimed that, "Happiness (happiness) is not the mere possession of money." He wanted Americans to understand that the joy of achievement is the path to happiness. Yet, even President Roosevelt would agree that earning an online college degree is a financially wise decision.