Algebra: a derivative from the arabic word "Al-Jaber"
algebra is one of the main branches of pure mathematics.
When unlike other branches, it uses letters to refer to unknown numbers, and you're usually required to figure out what number does the letter refer to.
Complicaited yes, but absolutely fun.
Unlike what some idiots stated, it can be use very frequently in daily life!
Algebra can vary from Elementary algebra which is the easiest, to Algebraic combinatorics.
Algebra is the best lesson in school, it can be a bit complicated yet very logical and easy.