What This Country Needs is an 18¢ Piece (2002) [pdf]
An old math paper arguing that the U.S. should add an 18-cent coin to minimize the number of coins needed for change prompts broader reflections on how currencies are designed and used. Commenters weigh the theoretical elegance of “optimal” coin systems against real-world behavior, from cash rounding practices in Europe and Canada to the political and lobbying forces that keep low-value coins like the penny alive. Many note that rising digital payments and inflation are steadily eroding the practical relevance of small denominations, even as cultural habits and legacy infrastructure slow formal reform.
Optimal coin systems and the 18¢ piece
- The paper’s 18¢-coin system is discussed mainly as a theoretical optimization of average coin count.
- Commenters note that greedy “biggest coin first” change-making fails with an 18¢ piece; you sometimes need exhaustive search.
- Some argue this makes it unrealistic in practice, since humans and simple registers rely on greedy heuristics.
Abolishing small coins and cash rounding
- Many argue the US should abolish pennies (and often nickels), given their tiny purchasing power and production cost.
- Canada and several Eurozone countries are cited as precedents: 1–2¢ coins withdrawn, cash totals rounded to 5¢; electronic payments still exact.
- There’s mild concern about rounding “ripping people off,” but examples from other countries suggest the effect is tiny and roughly symmetric.
- Some propose more radical simplifications (e.g., only quarters; or rebasing so 10¢ is the smallest coin).
Politics, lobbying, and inertia
- Explanations for the penny’s survival include:
- Interest-group lobbying, especially zinc suppliers and souvenir-coin interests.
- Political risk and low priority: killing the penny wins little but creates a ready-made outrage topic.
- General US resistance to “change,” likened to the slow metric transition.
International practices and inflation
- Examples from Canada, Netherlands, Sweden, Russia, Argentina, and Eurozone countries show:
- Cash rounding is already common and legally supported.
- Very small denominations naturally disappear under high inflation; prices implicitly rebase to larger units.
- Some note historical half-cent and pre-decimal British systems as comparisons.
Cash vs digital payments
- Several posters still prefer cash for privacy and resistance to financial surveillance.
- Others report rarely using cash and thus feeling little daily impact from coinage debates.
- There’s concern that fully digital money shifts power to private intermediaries and governments.
Coin usability and denominations
- Mixed views on $1 and $2 coins: some find them highly practical; others dislike coins vs bills.
- Various alternative systems are floated (e.g., 10¢/50¢/$1 only; $2.50 coin; duodecimal-inspired sets), but recognized as politically unrealistic.
PDF and font issues
- Separate subthread critiques the original PDF’s rasterized Computer Modern font.
- Commenters discuss TeX/METAFONT vs modern Type 1 fonts and show a process (pkfix) to regenerate a sharper version.