Algebra: A Piece of Cake, Part 1

Algebra helps our engaging teenage hostess, as she calculates the amounts of recipe ingredients needed to cook for and then serve, a sizable party:
1. To avoid confusion, when we write a formula we leave out the multiplication sign “x”, and instead put the number, the constant, in front of the variable, which is “X” in this case.
2. A formula, or equation, takes an input, does something mathematical to it, the rule, and produces an output.
3. Variables are symbols such as letters, which represent numbers. They make rules shorter and neater.
4. In algebra we often write division as a fraction, because it looks neater and because the ‘divided by’ sign can be mistaken for a ‘minus’sign.
5. We can write formulas for patterns