Fishtank Learning
8th Grade Math
Unit 4: Functions
Lesson 1
Objective
Define and identify functions.
Warm Up
In each set, numbers are input into a “black box” and then a number is output. Can you predict the last output in each set? Explain your reasoning.
|
Set 1 $$10 \rightarrow {\blacksquare} \rightarrow 25$$ $$5 \rightarrow {\blacksquare} \rightarrow 15$$ $$12 \rightarrow {\blacksquare} \rightarrow 29$$ $$8 \rightarrow {\blacksquare} \rightarrow ?$$ |
Set 2 $$1 \rightarrow {\blacksquare} \rightarrow 1$$ $$-1 \rightarrow {\blacksquare} \rightarrow 1$$ $$4 \rightarrow {\blacksquare} \rightarrow 16$$ $$-2 \rightarrow {\blacksquare} \rightarrow ?$$ |
Set 3 $$6 \rightarrow {\blacksquare} \rightarrow 3$$ $$8 \rightarrow {\blacksquare} \rightarrow 4$$ $$7 \rightarrow {\blacksquare} \rightarrow 0$$ $$11 \rightarrow {\blacksquare} \rightarrow ?$$ |
Anchor Problems - Problem 1
Your teacher will read you some questions and give you answer options. Move to the letter in the room that matches your answer.
Question 1: How many siblings do you have?
Question 2: How long did it take you to get to school today?
Question 3: What grade are you in?
Question 4: What color clothing are you wearing?
Question 5: In what month were you born?
Anchor Problems - Problem 2
For each situation below, fill in the missing information in the tables. Then determine if each chart represents a function.
a. A parking meter only accepts quarters. Each quarter (input) pays for 12 minutes of parking (output) up to 3 hours.
b. There are 15 players on a soccer team. Each player plays some amount of minutes (input) and scores some number of goals (output).
c. A pattern is created by starting with any number (input). If this number is greater than or equal to 6, it has an output 0. If this number is less than or equal to 6, it has an output of 1.
Anchor Problems - Problem 3
Four students, labeled A through D, represent the inputs, and four languages, shown below, represent the outputs.
Use an arrow to show a student speaks a language. For example, an arrow from “A” to “Portuguese” means student A speaks Portuguese.
In the left hand diagram, draw arrows to create a relationship between students and languages that is a function.
In the right hand diagram, draw arrows to create a relationship between students and languages that is not a function.
Problem Set
Target Task
In each example below, an arrow is used to show an input mapping to an output. Determine which relationships are functions. For each relationship that is not a function, explain why.
