A graphic artist is testing everyone’s knowledge of the mathematical order of operations with a string of numbers and missing arithmetic symbols. Gergely Dudás, of Budapest, Hungary, shared the new ...

Brain teasers like these have become popular on social media, where users enjoy testing their problem-solving speed and sharing their results. Experts say such puzzles stimulate logical thinking and ...

Quick: what’s 4 + 5? Nine right? Slightly less quick: what’s five plus four? Still nine, right? Okay, let’s wait a few seconds. Bear with me. Feel free to have a quick stretch. You’ve just performed a ...