Unit 4

Introducing Functions

What a function is, f(x) notation, domain & range, table/graph/equation/words

This unit is about one big idea: a function, a dependable way of matching each thing you put in to one thing that comes back. Almost everything later in the course is built on it. Working with simple equations and plugging numbers into expressions is what helps most here, so it's good to have those fresh.

Before you start, a small habit that pays off all through this unit: redo two or three problems from a lesson or two back from memory first. It takes a few minutes and makes the rest of the unit easier.

The one word to get solid is function. Once it is, every later topic is a function with a new name: lines, systems, sequences, and the U-shaped curves near the end.

So there's no rush here. The aim is to get comfortable, not to get fast. Each new piece builds on the arithmetic and the equation-solving from earlier units.