Choosing a Factoring Strategy
I can choose a factoring method by taking out the GCF first and counting the terms left.
What students learn
Students learn to take out the GCF, count the terms left to choose the difference of squares, a trinomial method or grouping, factor completely, and tell when a quadratic does not factor.
See inside
The key rule
Take out the GCF first. Then the number of terms left picks the method; check each factor before you stop.
2: a² − b²; 3: pair; 4: group
On this sheet, a quadratic with no pattern and no pair does not factor.
Watch out
A student factors 4x² − 100 as (2x + 10)(2x − 10).
The mistake: 4x² = 2x · 2x; 100 = 10 · 10It multiplies back, but 2x + 10 still shares 2.
The fix: GCF 4: 4(x² − 25) = 4(x + 5)(x − 5)Take out the GCF first; then nothing is left to share.
The mistakes it targets
- Uses a pattern before taking out the GCF
- Factors a sum of squares as a difference
- Writes a perfect square without testing the middle term
- Stops when the GCF is 1
- Stops before every factor is finished
- Drops the GCF from the final answer
The interactive Teacher Deck (31 slides, PowerPoint)
- The Learn page taught on screen: 8 fill-in blanks, each filled on its own click as students write it
- The worked example one slide per step (three steps), each with the reason for the step
- Six practice and three apply problems: a your-turn slide with a think-time bar, then the solution one line per click
- Jump buttons on every slide: go straight to any problem, the answer bank or the exit ticket
- Speaker notes on each problem: the question to ask, the worked answer and the common error to listen for
- A completed deck PDF (19 pages) with every slide fully built, to print or post
The student packet (9 pages)
- Learn: guided notes with four definitions, the key rule, a worked example and a Watch Out error pair
- Practice: two warm-up, two standard and two stretch problems, with an answer bank for self-checking that hides three common-mistake decoys
- Apply: one word problem, a reasoning prompt and one error analysis
- Assess: an exit ticket of four items, two per page, with an I-can self-rating
- Homework (page 5): eight new problems, two warm-up, four standard and two stretch
- Answer key (pages 6–7): every problem worked step by step, six common mistakes with what to do about each, and a grading guide, plus the homework key (page 8)
- Color and ink-saver editions of the whole packet
Standard codes refer to the Common Core State Standards for Mathematics. Math Class 678 is an independent publisher, not affiliated with, sponsored by, or endorsed by NGA Center or CCSSO. Every product is sold on Teachers Pay Teachers.