Riddles

1. Of decades, I’m a century.
Of pennies, I’m a dime.
I’m half a score, and nothing more.
A female chicken helps me rhyme.
What number am I?

2. Half a whole number and mixed up too.
If that’s not enough, consider this clue:
Greater than 3 and smaller than 4,
Guess what I am; I’ll tell you no more.

3. Some call me fifty-fifty.
I am a chance, it’s true.
It’s just as likely either way,
‘Cause I’m _______________.

4. I can be a factor,
But when doing times with me,
Your product’s always nothing!
What number must I be?

5. Take two of me as factors
If you really dare!
If it’s done with money,
You’re a millionaire!
There’s just a little more to say:
My name is M; my name is K.
What number am I?