Context: a conversation about an economics class in high school.
The Chinese Grammar Wiki says "以 A 为 B" means "using/taking A as B", but it still doesn't make sense to me.
An appropriate translation will be:
Aren't we supposed to do the report in small groups?
以小组为单位 literally means working as a unit (in small groups). The wiki is not wrong in translating 以 as 'using/taking'. The phrase simply means we should take 'small groups' as a unit to do the work.
The subject of the verb 要求 has been omitted in this case. Someone has apparently given the instruction to work in groups. That's why the speaker is asking to clarify the status of the instruction.
IMO, when 以...为... is used as a verb phrase, it should be translated to "using/taking A as B". For example, 他们以胖为美。== They take fat as beauty.
When it is used as a prepositional phrase, we could use the prepositional word by to interpret.
For example, 以小时为单位 could be simply translated to "by the hour". We are paid by the hour. == 我们以小时(为单位)计费。为单位 could be omitted in this case.
Apparently, in this context, it's a prepositional phrase. So,
one possible translation:
Isn't the demand/request to do the reporting by group?
Here 以小组为单位 could be interpreted as "by group".