What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

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

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

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?

Can you make a six-letter word using the letters N, A and B ?

What can you deduce from the following BrainBat?

CRY
LMKI

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

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

It is deaf, Dumb and Blind!!!

Still, always tells the truth. What is it?

A quarter is one-fourth of a dollar but Mr. John has changed the equation as below :

DOLLAR * 4 = QUARTER

Can you replace each letter with a digit to make the above solution correct?