Can you convert the number zero(0) into a positive number using just one mathematical operator ?

Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'

How can one talk without saying a single word?

You have an empty wine bottle with a cork that has been secured at the top in a normal way. There is a metal ring inside the bottle that is suspended by a string.

How can you make the metal ring drop to the bottom if you are not allowed to touch anything - not the bottle, not the cork, not the thread and not the ring?

What number should come in place of the question mark below?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

In a basket of apples,
when counted in twos, there was one extra
when counted in threes, there were two extra when counted in fours, there were three extra
when counted in fives, there were four extra
when counted in sixes, there was five extra.

However, if the apples were counted in sevens, no extra apple was left. Can you calculate the minimum number of apples that were present in the basket?

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

What does below Rebus mean ?

esgg sgeg gegs gsge

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?