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. At a running club, Ari writes each member's age and shoe size (some of the shoes are very muddy). Is it a function, and why?
- No: input 11 has two outputs, 4 and 6
- Yes: inputs 11, 12 and 13 each have an output
- No: input 12 has two outputs, 6 and 7
Read this first
Use the table
input: page output: stickers 4 6 1 3 3 6 2 5 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?
- No: inputs 2 and 4 both send an arrow to 8
- Yes: no two arrows land on the same output
- Yes: inputs 1, 2, 3 and 4 each send one arrow
Pia sorts library books onto shelves. The arrows go from book number to shelf number. Book 6 is huge, so it gets the bottom shelf. Is it a function, and why?
- Yes: inputs 1, 2, 3 and 6 each send one arrow
- No: inputs 1 and 3 both send an arrow to 2
- Yes: no two arrows land on the same output
(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
- No: input 3 has two outputs, 4 and 8
- Yes: inputs 1, 3 and 5 each have an output
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: (3, 2) and (3, 7) are on one up-and-down line
- Yes: no two points are at the same height
- No: the points do not start at (0, 0)
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
- Yes: each day has just one page count
- No: Monday and Wednesday share 12 pages
Use the table
input: minute output: birds 3 5 6 2 3 5 8 4 Milo counts birds at a feeder and writes (minute, birds). Minute 3 got copied twice. What is the domain (all the inputs)? List each value once.
Pia draws arrows from seed tray number to seeds planted. What is the domain (all the inputs)? List each value once.