Explore the art of mental math and estimation in this engaging 52-minute talk by bestselling author Rob Eastaway at The Royal Institution. Learn practical techniques for quick calculations, understand the risks of over-reliance on calculators, and discover how to make accurate estimations for everyday scenarios. Delve into amusing anecdotes, tackle arithmetic challenges, and gain valuable insights on topics ranging from metric conversions to probability. Enhance your mathematical intuition and problem-solving skills without the need for a calculator, as Eastaway demonstrates the power of back-of-the-envelope calculations and mental math tricks.