In the image below, can you find the value of an angle(y)

Decode below rebus
D
N
A
T
S , D

What does this rebus picture identify?

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?

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

You have a basket containing ten apples. You have ten friends, who each desire an apple. You give each of your friends one apple.
Now all your friends have one apple each, yet there is an apple remaining in the basket.
How?

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

I add 5 to 9 and get 2. The answer is correct, so what am I?

A high school has a strange principal. On the first day, he has his students perform an odd opening day ceremony:

There are one thousand lockers and one thousand students in the school. The principal asks the first student to go to every locker and open it. Then he has the second student go to every second locker and close it. The third goes to every third locker and, if it is closed, he opens it, and if it is open, he closes it. The fourth student does this to every fourth locker, and so on. After the process is completed with the thousandth student, how many lockers are open?

Can you replace the question mark with the correct number in the below table sequence?