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

Read also:

• News & Notes: John Harbaugh on Why Jon Gruden Observed OTAs - Baltimore Ravens
• The Y chromosome is disappearing, and this fact is already causing problems for men - Earth.com
• This Week In Space podcast: Episode 163 — The Trials of Starship - Space
• Why cant I ever fall asleep with my boyfriend?
• Porsche Built A One-Off Street-Legal 963 Hypercar For 88-Year-Old Roger Penske - Jalopnik
• What is the reason for writing X^2 as XX instead of X*X?
• Nuclear rocket engine for Moon and Mars - European Space Agency
• What to Know About Tyler Perry’s $260 Million Lawsuit - Vulture
• What is red light therapy? Can a normal LED bulb that we use in a room be used for red-light therapy for eyes?
• What was your first experience like with a black man?
• Why is Matt Gaetz being investigated but not Sarah (Tim) McBride? Why do we only care about grooming when it's the Republicans doing it?
• Former Player Gives Definitive Verdict on Knicks Firing Tom Thibodeau - Athlon Sports