If two's company, and three's a crowd, then whats four and five ?

Things are just as they seem, right? Well, check again.
Can you count the number of tigers in this picture ?

What has 88 keys?

What goes up but never comes down?

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

Can you replace the question mark with the correct number?

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?