By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

The following sentence is false. The preceding sentence is true.
Are these two sentences true or false?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

We have arranged an array of numbers below. What you have to do is use any kind of mathematical symbol you know excluding any symbol that contains a number like cube root. You can use any amount of symbols but you have to come up with a valid equation for all of them.

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

I shave every day, but my beard stays the same. What am I?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

Find the next number in the sequence

5 12 24 36 ?

Find the missing number in the sequence below:

Prove that twice of ten is the same as twice of eleven.