## Expression and Equation Building

Most books start off with the easy and mundane: How to work with numbers, and what is a number anyway. Besides regurgitating how to multiply, divide, add, subtract, exponentiate, distribute, factor, and generally mucking about with numbers, you learn about the different number types:

- Naturals
- Wholes
- Integers
- Rational
- Irrational
- Reals
- Complex (which comes much much later in math)

Each group has a specific type of number.

- Naturals are only counting numbers: 1, 2, 3, 4 …
- Wholes are Naturals + Zero: 0, 1, 2, 3, …
- Integers are Wholes but negative too: … -2, -1, 0, 1, 2 …
- Rationals are any fraction made of integers, they are also any decimal that repeats or stops
- Irrational numbers are strange, things like π, e, φ, √(prime), even made up numbers like 0.12345678910111213141516, there’s a pattern but no repeating
- Real numbers are all of the above
- Complex, well, we’ll get into those later, it has to do with what happens when you take the square root of a negative number

So, once you get all that down, you do some basic arithmetic and then you come upon expressions!

Expressions are math statements, sentences really, that don’t have an equal sign. That’s it!

An equation is composed of two expressions and an equal sign, nothing more. So, keep on your toes when you read, you’ll see both words and now you’ll know what you’ll be looking at and what you’ll have to do.