I remember Pi in the Sky by John Barrows very fondly. It has more of a focus on geometry and logic. A Programmer's Introduction to Mathematics by Jeremy Kun is wide ranging and appropriate if there is also interest in programming. Nature and Growth of Modern Mathematics by Edna Kramer is a wonderful book if history is a passion as well. Elements of Mathematics by John Stillwell is a broad overview of subjects. It has a crisp mathematical feel to it. Vector Calculus, Linear Algebra, and Differential Forms by John & Barbara Hubbard is a beautiful introduction to the multi-dimensional aspects, but it is a book that should happen after knowing one dimensional calculus. . If your child hasn't been exposed to Guesstimation, then a book on that is highly recommended. The book with that title by Weinstein and Adams is a nice guide to investigating that realm. If the child does arithmetic from right to left, as is sadly too common, the book Speed Mathematics Simplified by Edward Stoddard is a great remedy for that. Everyday Calculus by Oscar Fernandez could also be worth a look.
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