Is it a function? Inputs, outputs, domain and range
Grade 8 Math Worksheet - Building Confidence
Circle the best answer, or write your answer on the line.
Read this first
Use the table
input: bus number output: route length in miles 2 5 7 8 7 8 9 6 Rows sorted by input so repeated inputs sit side by side.
Bo writes each bus number and the length of its route in miles. Bus 7 passes twice, so it gets written twice. Is it a function, and why?
- Yes: inputs 2, 7 and 9 each have one output
- Yes: no input appears twice, so no bus repeats
- No: input 7 appears in two rows
Esme measures the plants on a classroom shelf. Plant 4 is the tallest and leans toward the window. Is it a function, and why?
- No: inputs 1 and 3 share the output 9
- Yes: inputs 1, 2, 3 and 4 each have one output
- Yes: no output appears twice, so no height repeats
Use the table
input: number typed in output: number shown 5 2 3 8 5 6 1 4 Jun's toy robot answers number questions, but it hiccups now and then. The table shows what went in and what came out. Is it a function, and why?
- No: input 3 has two outputs, 8 and 4
- Yes: inputs 1, 3 and 5 each have an output
- No: input 5 has two outputs, 2 and 6
Kira counts the stickers on each page of a sticker book. Page 1 has a shiny dragonfly. Is it a function, and why?
- No: inputs 3 and 4 share the output 6
- Yes: inputs 1, 2, 3 and 4 each have one output
- Yes: no output appears twice, so no count repeats
On field day, each team plays ball games on one field. Milo draws arrows from team numbers to field numbers. Is it a function, and why?
- Yes: no two arrows land on the same output
- No: inputs 2 and 4 both send an arrow to 8
- Yes: inputs 1, 2, 3 and 4 each send one arrow
Noah weighs boxes for a move. Box 3 got weighed twice on a wobbly scale. The arrows go from box number to pounds. Is it a function, and why?
- No: input 1 sends arrows to 4 and 6
- No: input 3 sends arrows to 6 and 9
- Yes: inputs 1, 3 and 5 each send an arrow
(3, 4), (1, 6), (3, 8), (5, 2). Zee picks carrots and writes (garden row, carrots picked). Row 3 got picked twice, once before lunch and once after. Is it a function, and why?
- No: input 3 has two outputs, 4 and 8
- Yes: inputs 1, 3 and 5 each have an output
- No: input 1 has two outputs, 6 and 2
Two friends count kites over the park each hour, and Bo plots both counts. At hour 3 they disagree. Is it a function, and why?
- No: the points do not start at (0, 0)
- No: (3, 2) and (3, 7) are on one up-and-down line
- Yes: no two points are at the same height
Luz checks the lunch seats: ticket 4 sits at table 2, ticket 9 at table 5 and ticket 13 at table 2. Input: ticket. Output: table. Is it a function, and why?
- Yes: no table number appears twice
- No: tickets 4 and 13 share table 2
- Yes: each ticket has just one table
(1, 7), (2, 4), (4, 7), (5, 9). Noah plants sunflower seeds and writes (day, seeds sprouted). What is the range (all the outputs)? List each value once.