Agreed and added to the errata for the comments for page 139, 353 and 476. For page 544, you are correct. This was already in the errata, but listed under page 572 which is the page on which the answer appears. Have a cow for your attention to detail.
For 242, this is either an English thing or I'm missing your point.
original text wrote: Leap years are years that are a multiple of 4 or 400 but not other multiples of 100
2000 - is a leap year because a multiple of 400
1900 - is not a leap year because not a multiple of 400, but another multiple of 100