â 8th Grade Math · Unit 4
Functions
19 short narrated lessons in 4 chapters, each with pictures, a quiz with a hint and a second try, and an explanation for every answer.
Standards: 8.F.A.1 8.F.A.2 8.F.A.3 8.F.B.4 8.F.B.5
What your child will learn
Introducing functions
- What Is a Function?Explain that a function gives exactly one output for each input.
- Functions in Tables and Mapping DiagramsDecide whether a table or mapping diagram shows a function.
- Graphs of FunctionsRead a function's graph as the set of ordered pairs of inputs and outputs.
- Introducing Functions: Review ReviewReview the meaning of a function and recognizing functions in tables and graphs.
Comparing functions
- Representing Functions Four WaysShow the same function with words, a table, a graph and an equation.
- Comparing Rates of ChangeCompare the rates of change of two functions shown in different ways.
- Linear and Nonlinear FunctionsTell whether a function is linear by checking for a constant rate of change or a straight-line graph.
- Comparing Functions Review ReviewReview representing functions, comparing them and identifying linear and nonlinear functions.
Linear models
- Rate of change and initial valueFind the rate of change and initial value of a linear function from a description.
- Linear functions from tablesWrite a linear function from a table of values.
- Linear functions from graphsWrite a linear function by reading the slope and y-intercept from a graph.
- Linear functions from two pointsWrite a linear function when you know two input and output pairs.
- Interpreting linear modelsExplain what the slope and starting value mean in a real situation like a phone plan.
- Linear models review ReviewReview building linear functions from descriptions, tables, graphs and two points and interpreting them.
Describing graphs
- Increasing and DecreasingDescribe where a graph is increasing, decreasing or constant.
- Interpreting Qualitative GraphsTell the story a graph shows, like a car speeding up, stopping and slowing down.
- Sketching Graphs from StoriesSketch a graph that matches a description of how one quantity changes with another.
- Describing Graphs Review ReviewReview describing and sketching graphs of real situations.
- Unit 4 Test: FunctionsShow what you learned in the whole unit (Introducing functions, Comparing functions, Linear models, Describing graphs) by answering mixed questions.
Try a question from this unit
From the lesson âWhat Is a Function?â
Jada's dog-walking rule takes the number of hours she walks dogs and gives how much she earns. In this rule, what is the input?
Show the answer
the number of hours she walks. The input is what goes into the rule, and here that is the number of hours. The money she earns is what comes out, so it is the output, not the input.
Hint kids see after a wrong try: âThe input is what you feed into the rule. Which quantity does Jada choose first?â
Key words
- function
- input
- output
- mapping diagram
- ordered pair
- graph
- representation
- rate of change
- linear function
- nonlinear function
- initial value
- table
- y-intercept
- two points
- model
- interpret
- increasing
- decreasing
- constant
- qualitative graph
- sketch
Try these lessons in Kids Shelf
Narrated lessons, pictures and quizzes for every grade from K to 8. Works offline.
