I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?

There is a box. The area of its top is 240 square units, the area of the front is 300 square units and the area of the end is 180 square units.

Can you calculate the dimensions of this box with the given data?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

Count the number of triangles in the picture below:

I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.

How many times can you subtract the number 5 from 25?

Can you find the thief by just looking at the picture below?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

I am a normal creature, but I have five hands. I can even have more but even then I will be considered normal.

Who am I?

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98