Learning the basic facts of addition, subtraction, multiplication, and division are an important part of any math foundation. I am a firm believer that every student, whether a child or adult, needs to know their basic facts, without using their fingers, a chart, or a calculator. Having a solid foundation and a firm understanding in this area will better equip a student for learning fractions, decimals, percents, algebra, geometry, etc. If a student does not knows their math facts, they will struggle in math all the way through school.
When learning or reviewing these facts, use a variety of methods and resources. Flashcards are cheap or free. Usborne makes a great Learning Wrap-up that allows hands on learning and self correcting. Steck Vaughn has a wonderful Number Power book. Learningtrends has free worksheets that can be used for reinforcement. Also check out Learningtrends free Quia interactive math activities.