The singular "farmer" is "agricola".
First Declension (Masculine Nouns)
Most first declension nouns are feminine, but there are several masculine words! These few words generally refer to male people.
It is a masculine word, but forms a plural and is inclined just like feminine words ending in "-a".
I said "they count the farmer's fields" (though I did forget an apostrophe in the actual thing). Since "agricolae" can also be genitive and dative singular as well as nominative plural, and since "numerant" without a said nominative means "they count", shouldn't my answer be accepted even if it wasn't what they were looking for?