If eleven plus two equals one, what does nine plus five equal?

What breaks yet never falls, and what falls yet never breaks?

When does a USA Potato change its nationality?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

You need to move three matchsticks to form three squares. Can you do it?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

If in a code language, DISTANCE is written as IDTUBECN and DOCUMENT is written as ODDVNTNE, the how will THURSDAY be coded as in the same language?

Thomas has missed an excessive number of days of school, so he must meet with Principal Davis. Mr. Davis asks him "Why on Earth have you missed so many days?" Thomas replies "There just isn't enough time for school. I need 8 hours of sleep a day, which adds up to about 122 days a year. Weekends off is 104 days a year. Summer vacation is about 60 days. If I spend about an hour on each meal, that's 3 hours a day or 45 days a year. I need at least 2 hours of exercise and relaxation time each day to stay physically and mentally fit, adding another 30 days. Add all of that up and you get about 361 days. That only leaves 4 days for school." The principal knows Thomas is full of it, but can't figure out why. Where is Thomas going wrong?

During which month do people sleep the least?