My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

What does this mean?

CCCCCCC

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

The following alphametic has only one solution. Can you find it?
ENLIST + SILENT + LISTEN = ANAGRAM

PS: You may start the number from 0.

Be active and find the killer in the picture Riddle below.

Some friends went on a vacation to a resort. It was raining heavily and it kept raining for thirteen days.

When it rained in the morning, the afternoon was beautiful and when it rained in the afternoon, the day was blessed with a clear morning.

Overall, the friends experienced eleven nice mornings and twelve nice afternoons. Can you find out the number of days they spent on vacation?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

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?