Slate, Paper or Phone: Cost per Thousand Exercises Priced Honestly

Practice requires somewhere to write. This paper prices three media per thousand exercises under stated lifetimes and yields: a slate, a paper exercise book, and photocopied worksheets. The slate wins on cost by a wide computed margin and loses on record-keeping, because its work is erased; the paper states both sides, and identifies the hybrid — slate for practice, paper for assessed work — as the cost-minimising pattern under the stated prices. Computed results: slate_usd_per_1000 = 0.37, paper_usd_per_1000 = 3.65, worksheet_usd_per_1000 = 7.5, slate_lifetime_exercises = 10800. Every number in this paper is produced by the accompanying script `compute.py`. SIMULATED, NOT MEASURED.