Equivalent Values.
Illustrated by Kevin O'Malley.
Four Stegosaurus for one Triceratops. Two Triceratops for one Allosaurus. It's the Dinosaur Card Trading Fair, and brothers Mike and Andy are wheeling and dealing, trying to make enough trades to get the ultimate card - the ferocious Tyrannosaurus Rex. True dinosaur facts on the cards are an added bonus in this story about equivalency, an elementary algebraic concept.
