jostylr

A Programmer's Introduction to Mathematics by Jeremy Kun is wide ranging and appropriate if there is also interest in programming.

Elements of Mathematics by John Stillwell is a broad overview of subjects.

Humorous, comprehensive, and, sadly, still as needed today as it was 20 years ago.

Everyday Calculus by Oscar Fernandez could also be worth a look.

The book with that title by Weinstein and Adams is a nice guide to investigating that realm.

I remember Pi in the Sky by John Barrows very fondly.

the book Speed Mathematics Simplified by Edward Stoddard is a great remedy for that.

Nature and Growth of Modern Mathematics by Edna Kramer is a wonderful book if history is a passion as well.

Vector Calculus, Linear Algebra, and Differential Forms by John & Barbara Hubbard is a beautiful introduction to the multi-dimensional aspects