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Printable Interval Mismatch Worksheet | Grade 9 Algebra I
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This worksheet teaches Grade 9 Algebra I students to find and fix mistakes in average rate of change work. Students check that endpoints match, units agree with the question, and inputs stay inside the domain, then rewrite each flawed solution correctly with units. The result is more accurate, better-explained rates of change.
At a Glance
- Grade: 9 · Subject: Algebra I
- Standard:
HSF-IF.B.6— Calculate and interpret average rate of change over a given interval- Skill Focus: Correct unit and interval mismatches in rate-of-change work
- Format: 5 pages · 10 problems · Answer key included · PDF
- Best For: Error analysis after rate-of-change instruction
- Time: 25–35 minutes
What's Inside
The 5-page PDF includes a conventions box, one worked model repair, five interval-mismatch problems in Part A, and five unit and domain problems in Part B. Students quote the error, explain it, and write corrected work with units. A full answer key is included.
Skill Progression
- Guided practice: 1 worked model repair, fully scaffolded.
- Supported practice: 5 Part A problems with an Error / Why / Correction frame.
- Independent practice: 5 Part B problems requiring unit and domain checks.
The sequence follows gradual release: I Do, We Do, You Do.
Standards Alignment
HSF-IF.B.6 — Calculate and interpret the average rate of change of a function, presented symbolically or as a table, over a specified interval; estimate it from a graph. This worksheet covers tables, function rules, point values, and one graph. The standard code can be copied directly into lesson plans, IEP goals, or district curriculum mapping tools.
How to Use It
- After direct instruction: assign Part A to pairs as guided error analysis.
- Before a quiz: assign Part B as independent review.
Formative tip: watch whether students label both endpoints before computing; skipping this step predicts repeat mismatches. Expect 25–35 minutes for the full set.
Who It's For
Grade 9 Algebra I students who can compute slope but slip on endpoints, units, or domain. Students needing support can start with Part A beside the worked repair. Pair it with an anchor chart of the average rate of change formula.
Standard HSF-IF.B.6 asks Grade 9 Algebra I students to calculate and interpret the average rate of change of a function over a specified interval. This worksheet targets the most common slips in that skill: pairing mismatched endpoints, reversing the order of subtraction, ignoring unit conversions, and leaving the stated domain. Students analyze 10 flawed solutions in a 5-page PDF, quote the error, explain why it is wrong, and write corrected work with units. The design follows the gradual release framework described by Fisher & Frey (2014), moving from a worked model repair to supported and then independent error analysis. Because every problem contains exactly one error, teachers can see whether a student understands why a rate is computed from one pair of endpoints and why its unit is output per input. A full answer key supports quick checking.
