How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

Replace the question mark with the correct number in below Picture:

What four weights can be used to balance from 1 to 30 pounds?

Can you place three balls such that the equation shown in the picture holds true?

By what process could you make a 'Tea-Table' into food?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

What demands an answer, but asks no questions

What 5-letter word typed in all capital letters can be read the same upside down?

A 3 digit number is such that it's unit digit is equal to the product of the other two digits which are prime. Also, the difference between it's reverse and itself is 396.

What is the sum of the three digits?

Can you count the number of matches in the picture below ?