Goal: classify roots and distinguish exact equality from approximation using Card A. Say: “The radical symbol alone does not make a value irrational.”
- 0–2: Recall
3^2=9,4^2=16; ask where 10 sits. - 2–7: Model
sqrt(9)=3and3<sqrt(10)<4, since9<10<16. Say thatsqrt(10)≈3.162is approximate. - 7–13: Partners classify the three sides; ask what “principal square root” means for a side length.
- 13–20: Learners show exact/approximate notation and explain why
sqrt(10)is a surd. - 20–25: Exit: can
sqrt(16)be called a surd here? Collect the reason.
Routes: write a three-row exact/approximate table; tell the comparison while a peer captures 9<10<16; arrange 9, 10, 16 square-number tiles and dictate the inequality. Other domains: Day 1 swaps. Optional/home: find two invented square areas, one perfect and one not, then classify side expressions on scrap paper. Move: if a learner says all radicals are irrational, replace 10 with 16; if they write =3.162, ask what symbol marks rounding.