What is the sum of X+XX+XXX+XXXX?

Read also:

• To Break a Bad Habit and Create a New One, Neuroscience Says Just Make One Simple Change - Inc.com
• The Biggest Pros And Cons Of Dodge's Hemi Engine - Jalopnik
• Baby Talk Enhances Infant Speech Learning - Neuroscience News
• NASA is already great. Right now. - NASA Watch
• Administration to phase out NIH support of HIV clinical guidelines - The Washington Post
• Anna Camp Defends 18-Year Age Gap With Jade Whipkey, Says She’s “Far More Mature” Than Male Exes - Yahoo
• A hidden 'super-Earth' exoplanet is dipping in and out of its habitable zone - Space
• Brain Adapts to Neuron Loss Through Rapid Rewiring - Neuroscience News
• Why do men like women gold diggers?
• Important scientific finding confirms ancient biblical events - The Brighter Side of News
• Why do Brits drive a lot more dangerously compared to Americans? Is there just no courtesy when driving in the UK?
• Being fat is a trap - Hacker News