## Set Sums

Prove that if any set of nine distinct integers has sum greater than 200, then there is a subset of four of the integers whose sum is greater than 100.

Source: unknown

View the solution

A Set of Rational Numbers

Trig Is Fun!

# Understanding Coronavirus Spread

A Question and Answer session with Professor Puzzler about the math behind infection spread.

# Blogs on This Site

Reviews and book lists - books we love!

The site administrator fields questions from visitors.

Like us on Facebook to get updates about new resources