Hammer = production
Commerce = gold/research (depending on research slider) income from tiles
A simple plain hill has 2 ''hammers'' production. If a city works it.
A plain hill with a mine will be 4 hammers. If a city works it.
A plain hill with a gold resource will be 2 hammers and 1 commerce. If a city works it.
A plain hill with gold, a mine will be : 3 Hammers, 7 commerce ( +6 from the mine). If a city works it.
See:
