Author note — to cover

Toggling between exact display (fraction, root, pi) and decimal with the S-to-D key, and reading the whole display before rounding. Only the toggle lives here: when exactness is demanded lives on exact-answers, and the ANS and memory keys live on calculator-ans-memory. Both tiers. (N8, N14)

• Fluency — direct questions on exact values, ans and memory, limited to this lesson's stated scope (4 questions).
• Application — use the same skill in unfamiliar or contextual questions without introducing a later method (4 questions).
• Check — questions built around the exclusions and likely misconceptions named in the lesson brief (4 questions).