Answer from cs61c-au (Robert Webb 14343043) for Question 2
A subnormal is a positive number less than one. (I think?)  It is called that because a normalized number in scientific notation has exactly one digit before the decimal point.  Therefore, following my skewed logic, subnormal would be having no digits before the decimal point....    I am doing the best with what I have to work with here.

We want to deal with them because very few things in the real world actually end up being integers.