You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

Kids with the most attentive eyes can spot a different watermelon in 4 seconds. Can you? Test your eyes now!

I am a type of food that is often found in the fridge and can be white in colour. What I am?
Hint 1: I am a dairy product.
Hint 2: You can spread me on the bread.

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

It can be easily calculated that the digits 0 to 9 can be arranged into 3628800 distinct ten-digit numbers.

But do you know how many of these numbers are prime?

How many times can you subtract the number two from the number fifty?

Give it food and it will live; give it water and it will die.

It is an eleven letter word.
The first, second, third and fourth letters form a banquet's name.
The fifth, sixth and seventh letters form a car's name.
The eighth, ninth, tenth and eleventh letters form a mode of transport.

Can you identify what word it is?

If six children and two dogs were under an umbrella, how come none of them got wet?