Ants Don't Catch Flying Saucers (Abby and Tess Pet-Sitters)

This award-winning series features Abby, an aspiring veterinarian who desperately wants a pet but lives in a "no pets allowed" apartment building, and her younger sister, Tess. The girls go into the pet-sitting business and discover new things about animals and new ways to solve problems.
In Ants Don't Catch Flying Saucers, Abby and classmate Dirk face-off. The way he always teases her and calls her names is so annoying! Now she's stuck on his team for the Crazy Olympics at school. To make matters worse, she has to pet-sit his ant colony over the weekend. But an accidental discovery shows Abby that bugs are more cool than creepy.