What always comes into a house through the keyhole?

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

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

If all Goats are Sheep and all Sheep are Deers, are all Deers Goats ?

Which English verb becomes past tense just by rearranging the letters?

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?

Can you decipher the two rows to find the hidden word?

0 0 0 = 6
1 1 1 = 6
2 2 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

You can use any mathematical symbols in the space provided to make all above algebraic expressions true.

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.