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 ...

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 ...

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 ...