Learn Finnish: Läksy on monimutkainen. - The homework is complicated.

It is a compound word built from moni (many) and mutka (bend, curve), followed by the common adjective suffix -inen. So literally, it means "having many curves," which is a great, visual way to describe something complicated!

This lesson is about adding verbs to these descriptions. How would I say "The homework is complicated to understand"?

You would say Läksy on monimutkainen ymmärtää. You simply add the basic dictionary form of the verb (the 1st infinitive) directly after the adjective, exactly matching the structure you are practicing in this lesson.

Could I flip the sentence around and say "It is complicated to do the homework"?

Yes, but the grammar changes! You would say On monimutkaista tehdä läksy. When a sentence starts with an abstract "It is..." evaluation, the adjective must be in the partitive case (monimutkaista). In our original sentence, the subject is a regular noun (Läksy), so the adjective stays in the basic nominative case.

In English, "homework" doesn't have a plural form. Is it always singular in Finnish like in this sentence?

No, Finnish actually uses the plural läksyt very often when talking about homework in general or multiple school assignments. If you wanted to use the plural here, you would say Läksyt ovat monimutkaisia. Notice that the verb becomes plural (ovat) and the adjective changes to the plural partitive case.