Answer:
I plow and plow but never sow.
I am essential to life on earth! I am split into thirds. Two thirds are the same. One of the thirds is 8. The other two are 1 each.
I am a house with two occupants sometimes one rarely three. Break the walls eat the boarders then throw away me.
Adored by few, feared and hated by many. Mistress of the entire universal reason, master in the art of numbers. Some may have solved many of my mysteries, but there are still many of them to find. What am I?
What is cut on a table but is never eaten?
No matter how little or how much you use me, you change me every month.