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

Read also:

• What is the more common way to say "you're welcome" in French: “De rien” or “Pas de problème”?
• Why does Islam give a bad vibe?
• Has anyone been spanked by their parents after becoming an adult?
• How would you define love?
• Why is it easy to make money in the USA?
• Why are men so attracted to big breasts?
• Do airline pilots try to avoid turbulence? How can you tell if your flight has been rerouted due to weather conditions or other factors?
• My ex got into a relationship within 2 weeks after a breakup. What should I do?
• Why do some people prefer watching movies than reading novels even if they are both based on the same source material (book)?
• Which country has the best and strictest legal system in the world?