Algebraic Expressions include numbers, variables and operations.
Numbers: 2, 5, 3.5, -9, 1/2, etc...
Variables: x, y, a, etc...
Operations: + - * etc...
How to write an expression.
a ton of practice on writing expressions
Source: You Tube
In general, algebraic expressions make it easy to see the relationships without needing so much wording. Look at how much shorter is it to write J - 3 instead of writing My sister, who has always been such a pain, is 3 years younger than I am. Here is another link to practice with algebraic expressions.
