Math Challenges Brain Boosters http://school.discovery.com/brainboosters/         There's much more here than just math challenges!!! Brain teasers http://www.eduplace.com/math/brain/         Select your grade level and find a new challenge each week. Let's Do Math http://math.rice.edu/~lanius/domath/index.html         Problem solving exercises - online. Create your own graphs http://nces.ed.gov/nceskids/Graphing/ Calculation fun http://www.coolmath4kids.com/calculators/index.html         Real-world application of math calculating skills.