The secondary school had no science laboratory, which meant that no pupil from that village had ever sat the practical papers, which meant that no pupil from that village had ever read medicine.
Everyone understood this. Nobody had counted it.
The notebook
A retired teacher did the arithmetic and wrote it on one page: what a laboratory cost, what the village earned in a season, and what proportion of one season’s surplus it would take. The number was large. It was not impossible, and until somebody wrote it down everyone had assumed it was.
They raised it over four years, in amounts small enough to be embarrassing to report and consistent enough to work. The building went up in the fifth.
What I take from it
The obstacle was not poverty. The obstacle was that a difficult number had never been separated from an impossible one, and the separation took a page of arithmetic that anyone could have done.
Three of that school’s pupils are now doctors. One of them wrote to me.