Being a chemistry professor, I usually have many students that struggle with simple mathematics skills. But, they need to improve quite fast to be able to survive the class (there are many complicated unit conversions). That means that they will have to work on it with worksheets, as that is the best way to gain those skills. I have found a few websites that have good practice worksheets that can help:
http://www.dadsworksheets.com/http://www.homeschoolmath.net/ Since I do not know at what level anyone is having difficulty with here, I am going to assume that it is below calculus level. Please try the sites above and let me know if they helped you or not. I do have other links, but I did not want to overwhelm with too much math at one time.
One more thing, never give up. It may get rough, but never falter in what you want to achieve when it comes to an education...