Mathematics 8

Common Misconceptions

Term 1 Week 7 · Factoring polynomials completely · CG Quarter 1, competency 8

#The misconceptionWhere it showsWhat to do
1 Only one factorisation can be correct §B, by design Expand all three. The arithmetic settles it, not the teacher
2 Incomplete means wrong Exit ticket item 1 Correct immediately. Factoring proceeds in stages and every stage is correct
3 A common factor of 2 "does not count" Answer B left as final 2x − 4 = 2(x − 2). A numerical common factor is still a factor
4 Complete means "as many brackets as possible" Learner writes 2(x−2)(x+2) as (2)(x−2)(x+2) and asks if it is more complete Both are the same. The 2 is a factor whether or not it has brackets round it
5 x² + 4 factors like x² − 4 Will appear on Day 3, but sometimes today Defer it explicitly: "Hold that question until Wednesday — it is a good one." Write the learner's name on the board beside it
6 Factoring is guessing Learners wait to be told Every answer is checkable by expanding. Nobody needs permission to know if they are right
7 The common factor must be a number 5x² + 15x → 5(x² + 3x), stopping there The bracket still has an x in every term. Push: "Look again."
Generated from: lesson-plan.md · Anticipated Misconceptions