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

Read also:

• A promising new HIV vaccine was set to start trials. Then came Trump's latest cuts : Goats and Soda - NPR
• News & Notes: John Harbaugh on Why Jon Gruden Observed OTAs - Baltimore Ravens
• Which certification is most valuable in the IT field, and why?
• Day One Highlights at Pro Tour Magic: The Gathering®—FINAL FANTASY™ - magic.gg
• Why do people keep denying the similarities between Latin and Italian by saying they are totally different languages when it’s obvious they sound similar?
• What do you think about Christie’s New York sale dedicated solely to art created with artificial intelligence (AI)? To what extent is AI art a legitimate form of art?
• Can I add pencil on top of my dry brush oil painting? Reason being it's easier to draw darker hair colour. Will pencil lead and oil paint interact and cause something horrible?
• A Fossil So Well-Preserved It Looks Like It Came From Yesterday—Here’s What It Reveals - The Daily Galaxy
• Why is there a lack of affordable housing in the USA despite a surplus of empty homes?
• The Planetary Society reissues urgent call to reject disastrous budget proposal for NASA - The Planetary Society