Depending on how good you are, it can be helpful to go right back to basics. A great many adults no longer remember how to calculate percentages or do long division, for instance, and if you feel unsure about this type of thing you should go back and give yourself a refresher course before starting anything more complicated. A good place to start is the BBC skills website where you will find all the core skills. Have a click through the different sections - there are different levels of difficulty, explanations, exercises and games.

Once you have the basics, it may be better to enrol in a course rather than struggling on alone. If you put 'adult education' plus the name of your town in a search engine, you can find your nearest provider, and essential maths is one of the subjects that adult education classes tend to be good at. It's not usually expensive either. Good luck.