Is it a function? Inputs, outputs, domain and range
Grade 8 Math Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
Read this first
Use the table
input: x output: y -2 5 1/2 3 4 -1 -2 5 3 3 6 0 Ren copies a rule table from the board and writes one row twice. Is it a function, and why?
- Yes: inputs -2, 1/2, 3, 4 and 6 each have one output
- No: the outputs do not change by the same amount each time
- No: input -2 appears in two rows
Tala checks a table on the whiteboard before the bell. Is it a function, and why?
- Yes: inputs -1, 0, 2.5, 3 and 5 each have an output
- No: input -1 has two outputs, 6 and 7
- No: inputs 2.5 and 0 share the output 4
Zee solves a puzzle-club table with six rows (and one very sharp pencil). Is it a function, and why?
- No: the outputs do not change by the same amount
- No: inputs 1 1/2 and 4 share the output 6
- Yes: inputs -3, -1, 0, 1 1/2, 2 and 4 each have one output
(4, -2), (-3, 5), (4, -2), (1, 0), (-3, 6). Two inputs repeat in Esme's list of points. One repeat is harmless; one is not. Is it a function, and why?
- No: input 4 appears in two pairs
- Yes: inputs -3, 1 and 4 each have an output
- No: input -3 has two outputs, 5 and 6
Jun plots six points in all four quadrants for a star map. Is it a function, and why?
- No: the points are in all four quadrants of the grid
- No: (2, -4) and (2, 1) are on one up-and-down line
- Yes: no two points are at the same height
Luz plots five points from a mystery rule, then squints at them. Is it a function, and why?
- No: (3, -3) and (3, 2) are on one up-and-down line
- No: (-4, 1) and (0, 1) are at the same height
- No: the points do not go through (0, 0), so it fails
The pond was 14°C at 9 a.m., 19°C at noon and 14°C at 6 p.m. Milo makes temperature the input and time the output. Is it a function, and why?
- No: the times are not evenly spaced, so the rule fails
- Yes: every temperature has a time
- No: 14°C goes with two times, 9 a.m. and 6 p.m.
Pia scans library books: barcodes 104 and 117 are two copies of Comet Kids, and 125 is Sea Maps. Input: barcode. Output: title. Is it a function, and why?
- Yes: no title appears twice
- No: barcodes 104 and 117 share a title
- Yes: each barcode has just one title
Ren plots five stops on a hiking map grid. What is the domain (all the inputs)? List each value once.
Jun's pairs make a function: (1, 4), (3, 6), (5, 4), (6, 9). Which new pair can join and keep it a function?
- (5, 1)
- (2, 6)
- (3, 8)