You can put this solution on YOUR website! Properties of numbers, and translating word-based numeric or geometric descriptions into numbers. We can form equations and expressions from the human language descriptions or pictures and the number properties allow finding formulas for any of several of the numbers in those formulas.
The number properties that you learn in Algebra are usually intuitively understandable, but in Algebra, you learn to read and say them formally. You learn to use variables instead of always needing specific constant values.