Is your child having difficulty with a particular math subject at school? Are you taking a college calculus course and could use some extra explanation of a topic? Does your child or you need help in other STEM (Science, Technology, Engineering, Math) subjects? Check out Khan Academy. Browse their wonderful math videos, from Singapore Math at grade school level all the way up to Calculus and Trigonometry at College level. These videos are great for that extra support understanding a new topic. Khan Academy has over 3,400 free videos on various subjects – math, science, computer science, finance & economics, humanities, etc.
Also, try the free Wolfram Alpha computational knowledge engine. Just click on a subject or, if the subject is not listed, type in what you want to learn about into the Wolfram Alpha search box and press enter. Here are some examples of how to use Wolfram Alpha to get help on algebra problems. Wolfram Alpha is also working on its Wolfram Educational Portal. Currently, the educational portal has courses on Algebra, Calculus and Pre-Calculus.