Making a load of @NclNumbas questions on functions. Strategy: start with a big question like "when is a function injective", then (1/N)
@NclNumbas then attack it from lots of angles, e.g. give partial def of f, then "f(b) = 2 and f is injective. What's b?" (2/N)
@NclNumbas The big question could be answered on paper, but since we can only mark numbers or multiple-choice selections, need to ask more detailed qs