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

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

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

Use the digits from 1 up to 9 and make 100.

Follow the rules.
=> Each digit should be used only once.
=> You can only use addition.
=> For making a number, two single digits can be combined (for example, 4 and 2 can be combined to form 42 or 24)
=> A fraction can also be made by combining the two single digits (for example, 4 and 2 can be combined to form 4/2 or 2/4)

Question: how can we do this?

Which is heavier: a ton of bricks or a ton of feathers?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

what's the probability of getting a king or a queen from a pack of 52 cards?

John was driving a bus and got stuck when passing through an underpass. Then came Jacob with a needle and got the bus out of the underpass.

What did the boy do?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.