I have feet, but no legs. Which animal Am I?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

What can go up a chimney down, but can’t go down a chimney up?

In the addition below, all digits have been replaced by letters. Equal letters represent equal digits and different letters represent different digits.
ABCABA
BBDCAA
ABEABB
ABDBAA
------- +
AAFGBDH
What does the complete addition look like in digits?

You are given with the following sum. Each of the letters can be decoded as a digit. If we tell you that D = 5, then can you solve it entirely?

DONALD
+GERALD
=ROBERT

The answer I give is yes, but what I mean is no. What was the question?

Buy me, smell me or deliver me, I do not change.

Who am I?

What is common among 11, 69, and 88?

John was writing his first book. After saving the document, he locked his laptop with a password and mentioned some phrases for the hint box.

A friend of his tried opening his laptop but found out that it was password protected. Following is the hint that appeared.
1 mobile 3 books 2 roars 1 night 4 balls 2 lighters 1 ghost 1 hat 3 watches.

Can you help him in cracking the password?