Learn Farsi: فصل پنجم مهم است چون سخت است. - The fifth chapter is important because it is hard.

"Fifth" is panjom, formed by adding the suffix -om to the number five (panj). Ordinal numbers ending in -om act just like regular adjectives in Farsi. This means they must come after the noun and connect to it using an Ezafe. That's why we say fasl-e panjom instead of putting the number first.

Why isn't the Ezafe linking fasl and panjom visible in the Farsi text?

The Ezafe (the short "e" sound connecting a noun to its adjective) is almost never written in the Persian alphabet unless the first word ends in a vowel. Since fasl ends in a consonant, the Ezafe is invisible, but you still must pronounce it as fasl-e panjom.

I thought fasl meant "season". Can it also mean "chapter"?

Yes! Fasl is the exact same word for both "season" (like winter or spring) and "chapter" (in a book or a TV series). The context here makes it clear we are talking about a book or course because a season wouldn't normally be described as "hard" to learn.

Is chon the only word for "because"?

Chon is the most common, everyday word for "because" in spoken Farsi. You might also remember baraye inke from earlier lessons, which means the same thing and can be used here too, but chon is shorter and very natural for linking sentences like this.