Who Is Bigger? Who Is Smaller?

A pair of accordion-fold, cardstock books by Caroline Arnold helps youngsters understand size and numbers. Who Is Bigger? Who Is Smaller? shows farm animals of ascending sizes on one side, then their descending sizes on the other, from a mouse to a horse and back again. Who Has More? Who Has Fewer? adds a fun wrinkle: each bird pictured has one more egg than the previous; on the book's reverse, the number of baby birds, now hatched (from the eggs on the flip side), decreases. (July) .