Translation:We consider Saturday the sixth day of the week here.
Is 'Saturday is considered the sixth day of week here' really wrong here?
One of the native CZ contributors may provide additional information, but I'd suggest that since this sentence is in the active voice and the verb is "we consider," the translation given above is the most accurate. (Strictly In terms of meaning, of course, they're about the same.)
From time to time, I can imagine recognizing the opposite-voice translation (active vs. passive). However, in this exercise there is a shift in meaning. In the active voice, "we" are a part of this considering, we are on board. In the passive, the ownership is avoided, and the speaker may or may not be part of a group that considers Saturday as the sixth day.
If the meaning is not preserved, we only tend to recognize opposite-voice (or otherwise grammatically shifted) translations if the directly corresponding expression is missing or is unnatural on one or the other side of the translation. Here you would have to make the argument that "We consider...here." is unnatural in English or that "...je zde považována..." is unnatural in Czech.
why not? here we consider saturday to be the sixty day of the week