What does this mathematical rebus means ?

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

There is a number which when you multiply by 3 and subtract 2 from the result, then the resulting number is the reverse of the actual number.

What is the smallest number that stands true on the statement?

Can you count the number of triangles in the given figure?

In case you were starting to feel confident, this one was meant for third graders in Vietnam. The answer is 66, but we don't blame you for scratching your head about how they got there.

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

On a certain day, John celebrated his birthday. Two days later, his older twin brother Jacob celebrated his birthday.

Is this even possible? How can it be?

Count the number of lines in the image below ?

I shave every day, but my beard stays the same. What am I?

There was an aeroplane crash, every single person died, but two people survived. How is this possible?