Learn German: Das Hotel hat sechzig Zimmer. - The hotel has sixty rooms.

When building tens, you usually add -zig to the base number. However, the number sechs (six) drops its final s to make sechzig easier to say. The same thing happens with seventy, where sieben drops its en to become siebzig.

The English translation says rooms, but isn't Zimmer a singular word?

In German, many neuter and masculine nouns that end in -er don't change their spelling in the plural. Das Zimmer means the room, and die Zimmer means the rooms. You can tell it means rooms here because of the number sechzig.

How is the ending of sechzig pronounced?

In standard German, the -ig at the end of a word is pronounced like the soft ch sound in ich. In southern Germany and Austria, you will often hear it pronounced as a hard k sound instead. Both ways are perfectly understood by native speakers!

Why is the verb hat used here instead of haben?

Das Hotel is a singular thing (it), so we need the he, she, or it form of the verb haben (to have). Just like in English where we say the hotel has instead of the hotel have, in German we use the third-person singular form hat.