Learn Finnish: Taulu varastettiin museosta. - The painting was stolen from the museum.

In standard Finnish, when a sentence is in the passive voice, a singular complete object takes the basic form (nominative) instead of the -n ending (genitive/accusative). Because the action is passive, it is just taulu, rather than taulun.

How do we get the form varastettiin from the dictionary verb varastaa (to steal)?

To form the passive past for a verb type 1 ending in -a or -ä (like varastaa), you drop that final vowel, replace it with -e-, and add the passive past ending -ttiin. So, varastaa becomes varaste- + -ttiin, resulting in varastettiin.

Why do we use the ending -sta in museosta?

The ending -sta (the elative case) means "out of" or "from inside" a place. Since a museum is a physical building that you go inside, Finnish uses the inner location cases for it. Therefore, "from the museum" translates to museosta.

I learned that taulu means a blackboard or whiteboard. Can it also mean "painting"?

Yes! The word taulu broadly refers to a flat, often framed, rectangular object. Depending on the context, it can mean a classroom board, a chart, or a framed picture/painting hanging on a wall.