Can we take a second to appreciate the date??
Number theory... ish
Can you find an interval of 999 numbers such that there are no primes in that interval?
Hint: Look at factorials. Big ones.
Logic
Easy:
Why is it true that all frogs speak the truth?
Hint: vacuums...
Less Easy:
There is a magic frog which always speaks the truth, has a favourite number out of 1,2,3 AND speaks fluent portuguese. With only one yes or no question and google translate, what can you ask the frog to figure out his favourite number?