What does this rebus puzzle means ?

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?

John walks into the daily grocery shop and steals a $100 bill from the shop. An hour later John returns to the shop and buys some daily products for $40. John pays the owner the $100 bill and therefore the owner returns him $60.

How much money did the owner lose?

What can you deduce from the following BrainBat?

CRY
LMKI

Can you make four (4) nines (9) equal 100?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

How many triangles are there in the picture below?

Can you identify the famous TV character from the rebus below?

It is always ahead of me yet I can never see it. What is it?

I have a big mouth and I am also quite loud! I am NOT a gossip but I do get involved with everyone's dirty business.