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

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

Find the number of squares in the below picture

Count The number of F's in the paragraph below:

"FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS"

Keyboard words are not in alphabetical order, Why?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

What is the largest number you can write with just 3 digits?

What has one eye, but can’t see?

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

Astrology starts with the alphabet A, Biology starts with B, Psychology with P and Limnology with L.

Can you find an "ology" that begins with a P?