You’re at the checkout screen after an online shopping spree, ready to enter your credit card number. You type it in and instantly see a red error message ...

Prime numbers are all the rage these days. I can tell something’s up when random people start asking me about the randomness of primes—without even knowing that I’m a mathematician! In the past couple ...

Multiplication of two numbers is easy, right? At primary school we learn how to do long multiplication like this: Methods similar to this go back thousands of years, at least to the ancient Sumerians ...