Solve the mathematical equation in the picture below.

I am quite hot but become too cold if you remove the first two letters. What am I?

There are 100 bulbs in a room. 100 strangers have been accumulated in the adjacent room. The first one goes and lights up every bulb. The second one goes and switches off all the even-numbered bulbs - second, fourth, sixth... and so on. The third one goes and reverses the current position of every third bulb (third, sixth, ninth? and so on.) i.e. if the bulb is lit, he switches it off and if the bulb is off, he switches it on. All the 100 strangers progress similarly.

After the last person has done what he wanted, which bulbs will be lit and which ones will be switched off?

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

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

From a pack of 52 cards, I placed 4 cards on the table.

I will give you 4 clues about the cards:

Clue 1: Card on left cannot be greater than the card on the right.
Clue 2: Difference between the 1st card and 3rd card is 8.
Clue 3: There is no card of an ace.
Clue 4: There are no face cards (queen, king, jacks).
Clue 5: Difference between the 2nd card and 4th card is 7.

Identify four cards?

Can you find the key in the picture below?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

What is the largest number you can write with just 3 digits?

By moving just one matchstick, you need to make the below statement true. Can you do it?