Calculators are awesome, but they’re not always handy. More to the point, no one wants to be seen reaching for the calculator on their mobile phone when it’s time to figure out a 15 percent gratuity. Here are ten tips to help you crunch numbers in your head.
Mental math isn’t as difficult as it might sound, and you may be surprised at how easy it is to make seemingly impossible calculations using nothing but your beautiful brain. You just need to remember a few simple rules.
Add and Subtract From Left to Right
Remember how you were taught in school to add and subtract numbers from right to left (don’t forget to carry the one!)? That’s all fine and well when doing math with pencil and paper, but when performing mental math it’s better to do it moving from left to right. Switching the order so that you start with the largest values makes it a bit more intuitive and easier to figure out. So when adding 58 to 26, start with the first column and calculate 50+20=70, then 8+6=14, which added together is 84. Easy, peasy.