The rule of thumb for Study Time Committment for a University course is

Math 142 is a 4 credit unit course so you should be doing about 4x4=16 hours of studying Math 142 a week (outside of class).

Of course, this rule of thumb assumes you are well prepared for the course. Thus, if you are weak on some of the prerequisites, then you will need to do MORE.

A student wrote me:

By the way, I am loving Cramster for homework help. It helps with the little things I am stuck on. I feel like there would be a lot less to go over during recitation if everyone else used it as well.