I noticed a peculilarity today. I found a big chart on Wikipedia with a bunch of little particles on it. You can find it here: http://upload.wikimedia.org/wikipedia/en/4/4c/Particle_chart.jpg [Broken] So anyways. According to the chart, a proton is composed of two up quarks and one down quark. Also acording to this chart, a down quark has a mass of 0.006 GeV, and and ups have a mass of 0.003 GeV. Adding these up, it does not come anywhere near the 0.938 GeV of a proton! What am I doing wrong here? Am I just that out of practice with math? Are the figures depicted on the chart incorrect? Or do I need to know some advanced form of adding things up?