I am even, add one letter and I'm odd. What am I?

Answer: Seven.

More Medium Riddles with answers

More Medium Riddles

I am everything. I am nothing. I can make you tremble in fear or make your sadness disappear. I've been with you since you've arrived and I will be with you at the moment you die. We've know each other for our entire lives. I know you but you create me so what am I?
I am found in the sea and on land, but I do not walk or swim. I travel by foot, but I am toeless. No matter where I go, I'm never far from home. What am I?
I am from the month of December. I am not a holiday. I am the only month that has this. What am I?
I am green all over, yet I know no bounds. If you turn me around a face you will see, being without me produces envy. What am I?
I am heard before I am seen. Startled and I am alive. I rumble like thunder, yet I pour like rain. I am felt before I arrive; stand with me and you won't survive. What am I?
I am in a Tiny word. If you remove me I become metal. What am I?
I am in your eye. I am a school child. I am a word of five. What am I?
I am invisible, yet everywhere. Yet I am everywhere, I am not active in some places. Sometimes, you can feel me. I can be so strong, I can push you, and even destroy villages and towns. Yet I come unnoticed, you can make me. What am I?
I am large as a castle, yet lighter than air. 100 men and their horses cannot move me. What am I?
I am not a person nor an animal. I was born from the death of something large and hot. I am capable of consuming anything and everything. I am very dark and exists in a place where there is no gravity. What am I?
I am nothing, I am everything. I am perfect dark, I am the brightest lights. I am hungry, I am full. I am nowhere, I am everywhere. I am unseen, I am watched by millions. What am I?
I am one with eight to spare, lest I lose my one. I'm not a number. What am I?