Whether you’re calculating a tip or just in need of some fast math, percentages can be something even math students goof. This video from YouTube channel MindYourDecisions shows you the easiest way to find those numbers in your head. Read the rest of the article The Moscow Puzzles: 35… Kordemsky, Boris A. Best Price: $2.30 Buy New $7.00 (as of 11:45 EST – Details) Melissa & Doug Abacus … Buy New $12.50 (as of 08:45 EST – Details)