אבן עזרא — וזאת התרומה אשר תקחו / זהב וכסף ונחשת

Q — The Torah introduces the list of mishkan materials as "תרומה מאת כל איש אשר ידבנו לבו" — donated voluntarily. But kesef (silver) appears in the list, and the only kesef in the mishkan is the "כסף פקודי העדה" — half-shekel collected as obligatory tax, not donation. So how can kesef appear among the נדבה items? Rashi (and Rav Saadya Gaon) answered that there was a SECOND kesef donated for vessels not described in the parshiyot.

A — Ibn Ezra dismisses this as unnecessary. The kesef in the list IS the half-shekel; it was indeed obligatory. But the Torah uses a single descriptor for a list of sixteen items even though one of them doesn't strictly fit the descriptor — "הכתוב לא חשש להוציא דבר אחד מששה עשר דברים, כי החמשה עשר היו נדבה." Same principle as Binyamin in "ילד לו בפדן ארם" (born in Canaan), and Menashe/Ephraim in "ירדו אבותיך מצרימה" (born in Egypt). The Torah groups by majority — "אחר הרוב" — without surgical accuracy at every margin. This is the same principle Ibn Ezra developed at length in Vayigash about Yaakov in the 70.