0–4 orient: Put “no setup fee” beside “must cost less”; ask whether one missing fixed charge settles every quantity. 4–9 source read: Attribute the Trail Table handout, then reveal both model rules. 9–16 model: On the rate/base mat, form A(q) = 12 + 0.40q and B(q) = 0.65q; use q=40 for a check before any calculator. 16–27 route: Learners test 40 and 60 using number lines, a tactile fixed/variable strip or a narrated equation. 27–32 audit: Ask for the condition at which the preferred plan reverses, without needing to solve the exact crossing point. 32–35 exit: One source-grounded sentence for 40 and one for 60, with printing-only limit.
Development draft · local review needed
Day 13 · The invisible base chargeYear 11 Inquiry · T1 W3–4 · Day 13 lesson
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Year 11 / Integrated / Term 1 / Weeks 03 04
Part of the full two-week lesson sequence. Check the pack guide and taught point before teaching.
Open for this lesson: Pack guide · Fresh learner checks · Aids and text routes.
Teacher copy: This page may include teaching prompts or answer keys. Answer keys in this public library can be viewed by anyone. Give learners a clean prompt, use checks as formative evidence, and change a case locally when prior access matters.