A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water.

How many frogs are there on the log at this moment?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

What has many keys but can’t open a single lock?

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

What word begins and ends with an E, but has only one letter?

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"

Can you find the missing piece of the Porsche?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.