Each of these new books in the Math World series walks readers through a basic math concept via a fictional story that makes the process feel less like work. Explanations are built into the dialogue, and the characters and scenarios in the stories, set either at home or in a school classroom, are realistic and relatable. In Measure It, students use various units to measure the length of special objects they have brought to class. The stories typically end on an upbeat note, with a silly joke or clever ending. Longhi's illustrations, focusing on ethnically diverse characters, add great charm to the series. However, the large amount of dialogue and the number of characters in each book distract somewhat from the math concepts themselves. The presentation of these concepts is perhaps not clear enough for a first introduction, although these appealing books are still great for review.

So-so stories introduce math concepts: a boy learns about money while holding a yard sale; children make tally charts, bar graphs, pictographs, and pie charts from survey results; and children measure--in paper clips, then centimeters--their show-and-tell items. Mildly amusing illustrations reinforce the math. Change, unfortunately, is somewhat confusing: it's not always clear who the speaker is. Reading list, websites.