Can you replace the question mark with the correct number?

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.

How is a fly different from a mosquito?

The more of this there is, the less you see. What is it?

There is so small cabin inside a deep forest.
All the forest burned out to worst possible but the inside of the cabin is still the same.
However all the person inside the cabin die.

How come ?

Using eight eights and addition only, can you make 1000?

In the Thar desert, 3 men found a big 24L Jar is full of water. Since there is a shortage of water so they decided to distribute the water among themselves such that they all have equal amounts of it. But they only have a 13L, a 5L and an 11-litre Jar.

How do they do it?

How many times do a clock's hands overlap in a day ?

Replace the question mark in the picture below.

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?