It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Using Only Five 5's and any mathematical operator make sum as 37

What's the only room from which no one can enter or leave

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

Replace The Question Mark Below With the Correct Number.

2 {38} 3
4 {1524} 5
6 {3548} 7
8 {????} 9

Can you find the dog hidden in a group of pandas?

In four steps you need to move the word 'cold' From 'warm' by replacing one alphabet at a time such that every word formed at each step is acceptable in English Dictionary.

Count the number of balls in picture below:

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?