Can you write down eight eights so that they add up to one thousand?

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

What goes up but never comes down?

Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be ?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

Who always enjoys poor health?

Find the number of squares in the below-given picture.

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

How can you take 2 from 5 and leave 4?