I lost a possible job because I didn't know how to multiply and subtract negative valued integers. I also don't know how fraction manipulation works. What reference books can I read that can help for me to learn all the basics of math then moving forward to high school and college material?
My profession requires math so I think I really need this.
This question is somewhat related to Tips for an adult to learn math -- from the beginning..
I'm looking for books or apps.
Update: I've signed up for Khan Academy and it is quite great, but it seems that all the lessons in there are in form of videos. I won't go into specifics but the ISP industry is one of the greediest right now and they implement caps, so if you know any non-video lessons that will surely help, hence why I stated books or apps. Khan Academy is great for monitoring progress though, and I will keep my account on it.
Another update: Actually, Khan Academy has an offline version called KA Lite, you still need to download their videos though, but this is immensely helpful if you want to set up dedicated machines for people to learn. Their logo is "65% of the world lacks internet access. 100% of the world needs education." which I agree on 100%.