As members of a swim team do laps to qualify for swim camp, readers can practice subtracting two-digit numbers to see how many laps are left to go.

While trying to save enough money to buy a new ice scooter, Perry the Penguin learns about managing his money and about negative numbers.

An old map leads the members of the Elm Street Kids' Club to a buried time capsule.

Polly's got a pen pal - in Canada! Polly's sure that she and her new friend, Ally, will have a lot in common. When Ally writes that she's 125 centimeters tall and weighs 25 kilograms, Polly wants to know if she's the same. Polly wishes she could go and visit her -- but Ally lives 450 kilometers away! Young readers will learn about metric units like centimeters, kilograms, kilometers, and liters as they follow this story of two friends who can't be...