Co-authors Robert and Ellen Kaplan are husband and wife. Robert Kaplan has taught mathematics (most recently at Harvard Universtiy). He also taught Greek, German, Sanskrit and inspred guessing. In addition to teaching mathematics at Harvard University, Ellen Kaplan has taught history, Latin and biology. Together they have founded The Math Circle, a school for the enjoyment of pure mathematics.

Co-authors Robert and Ellen Kaplan are husband and wife. Robert Kaplan has taught mathematics (most recently at Harvard Universtiy). He also taught Greek, German, Sanskrit and inspred guessing. In addition to teaching mathematics at Harvard University, Ellen Kaplan has taught history, Latin and biology. Together they have founded The Math Circle, a school for the enjoyment of pure mathematics.

Co-authors Robert and Ellen Kaplan are husband and wife. Robert Kaplan has taught mathematics (most recently at Harvard Universtiy). He also taught Greek, German, Sanskrit and inspred guessing. In addition to teaching mathematics at Harvard University, Ellen Kaplan has taught history, Latin and biology. Together they have founded The Math Circle, a school for the enjoyment of pure mathematics.