Learn Polish: Spadkobiercy równo podzielili majątek. - The heirs divided the estate equally.

Yes, you can! Both równo and po równo mean 'equally' and are often used interchangeably with verbs of dividing. Using po równo emphasizes the distributive idea that 'each person got an equal share', which perfectly matches what you are learning in this lesson.

Why is the plural of 'heir' spadkobiercy? Doesn't the singular end in -a?

Exactly! The singular is spadkobierca, which ends in -a. But because it refers to a male person, it is treated as a masculine personal noun. Just like mężczyzna (man), it takes a masculine personal plural ending. Since the stem ends in -c, it takes -y to become spadkobiercy.

Is the po- at the start of podzielili related to the preposition po?

Here, po- acts as a prefix to turn the imperfective verb dzielić (to divide) into the perfective podzielić (to have divided completely). It isn't the standalone distributive preposition you are studying, but the prefix po- often carries a similar feeling of distributing an action among multiple people or parts.

Why does majątek look like it is in the Nominative case if it is the object being divided?