Anyone remember the story about the re-discovery of manual arithmetic enabling unmanned robot planes to be re-manned? I believe it was a short story published in Astounding.
This is most likely "The Feeling of Power" By Isaac Asimov, as suggested in [this eye-opening answer] by Valorum.
The idea that humanity struggles with simple arithmetic is clear
"Aub! How much is nine times seven?" Aub hesitated a moment. His pale eyes glimmered with a feeble anxiety. "Sixty-three," he said. Congressman Brant lifted his eyebrows. "Is that right?" "Check it for yourself, Congressman."
Valorum's answer to: Story about a mathematics discovery that would allow people to replace computers in missiles
and the "drones" which are actually missiles which are currently on auto-pilot are replace by human pilots.
The general drove on. "At the present time our chief bottleneck is the fact that missiles are limited in intelligence. The computer controlling them can only be so large, and for that reason they can meet the changing nature of anti-missile defenses in an unsatisfactory way. Few missiles, if any, accomplish their goal, and missile warfare is coming to a dead end, for the enemy, fortunately, as well as for ourselves.
"On the other hand, a missile with a man or two within, controlling flight by graphitics, would be lighter, more mobile, more intelligent. It would give us a lead that might well mean the margin of victory.
This story was published in If (as User14111 says) and can be read online here.