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.
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
Read this first
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?
- Yes: inputs 1, 3 and 5 each have an output
- No: input 5 has two outputs, 2 and 6
- No: input 3 has two outputs, 8 and 4
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: no output appears twice, so no count repeats
- Yes: inputs 1, 2, 3 and 4 each have one output
(2, 7), (4, 1), (6, 3), (2, 5). Ren logs (day, laps run) at the track. On day 2 there were two runs, morning and evening. Is it a function, and why?
- Yes: inputs 2, 4 and 6 each have an output
- No: input 2 has two outputs, 7 and 5
- No: input 4 has two outputs, 1 and 3
(1, 3), (2, 5), (3, 5), (5, 8). Tala weighs a puppy each week and writes (week, pounds). In week 3 the puppy chewed a sock, but only the weight counts. Is it a function, and why?
- Yes: no output appears twice, so no weight repeats
- Yes: inputs 1, 2, 3 and 5 each have one output
- No: inputs 2 and 3 share the output 5
(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 1 has two outputs, 6 and 2
- Yes: inputs 1, 3 and 5 each have an output
- No: input 3 has two outputs, 4 and 8
At camp, Jun hands out shirts: one 11-year-old gets M, a 12-year-old gets L, and another 11-year-old gets S. Input: age. Output: shirt size. Is it a function, and why?
- Yes: every age has a shirt size
- No: age 11 goes with two sizes, M and S
- No: sizes are letters, not numbers
Kira's reading log: 12 pages on Monday, 9 on Tuesday and 12 on Wednesday (the book got exciting). Input: day. Output: pages read. Is it a function, and why?
- Yes: no page count appears twice
- No: Monday and Wednesday share 12 pages
- Yes: each day has just one page count
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: each ticket has just one table
- No: tickets 4 and 13 share table 2
- Yes: no table number appears twice
Pia draws arrows from seed tray number to seeds planted. What is the domain (all the inputs)? List each value once.