Why is Bamidbar 28:16 read as the first passuk of Maftir on the first day of Pesach if that passuk has nothing to do with Pesach, rather it refers to the Korban Pesach which was brought the day before on Erev Pesach? And don't tell me that it's because we read that entire Parsha regardless of its relevance to the specific day, because on all other days of Pesach we begin reading from Numbers 28:19 and skip Numbers 28:16-18 because those verses are irrelevant to the latter days of Pesach.
Perhaps by rights it's true that on the first day (or two days) we should start with 28:17, but then we'd be violating the rule that we don't begin an aliyah within three verses of a parashah break (open or closed). On the other hand, verse 19 is already three verses away from the parashah break, and so there's no problem starting there on Chol Hamoed.
First of all, it's kri'as hatorah.
Secondly, when do we eat the korban pesach if not on Pesach.
Besides Alex's answer, if the first pasuk were skipped, the date of the chag would only be known as the 15th. The first pasuk clarifies the month.