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?

I have a sore throat and a severe headache. I have four tablets with me that are identical to each other and they do not have any cover on them. There is no way I can identify which tablet serves what purpose. The only thing that I know is that two of these four tablets are for the throat and the remaining two are for the headache. To treat my condition, I must take 1 of each. What will I do now?

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?

What is the word or phrase?

Identify the hidden meaning behind this picture?

In the below-given picture of a pretty girl, there is something wrong. Can you find out what it is?

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

Can you complete the sequence puzzle?

AR TA GE CA LE VI LI _

John: "Hi Teacher, What is your favourite movie ?".
Chemistry Teacher: "Indium Cerium Platinum Iodine Oxygen Nitrogen".
Ten seconds later... John replied I got it.

Do you?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?