Your Brain Needs Numbers
Like many, I’m hopelessly dependent on my iPhone, and one of my most-used apps is the Hewlett Packard 10bii Financial Calculator. You have to really know that calculator to pass the Certified Financial Planner exams, and for good reason: It allows you to calculate cashflow and present/future value projections. The nerd in me really has a lot of fun using it, which got me thinking of the importance of numbers, and math formulas in particular, to keep our cognitive functions sharp.
Basic math can be helpful for those dealing with dementia as well. Puzzles like Sudoku encourage the brain to work through logic and memory issues. Sudoku is a number puzzle and the gameboard can be designed for all levels of difficulty; from very easy for those with some cognitive issues, to very difficult for those ready for the challenge. A math puzzle like Sudoku is like a bench press for the brain.
Not long ago I started setting my calculator down and attempting to write out some basic math formulas just to get back in the swing. It is both amazing and embarrassing as to how much I forgot. Here are a few math tricks to motivate you to set down the calculator occasionally:
- When multiplying a 2-digit number by 11, place the sum of the 2 digits between those digits to get the answer. 45 x 11 (4+5 = 9), so 495 is the answer. It works with any 2-digit number multiplied by 11. If the sum of the numbers is 10 or more, it still works, but you add the first digits, place the second digit of the answer in the middle… and remember to carry the 1; 56 x 11 (5+6 = 11, carry the 1, 5+1 = 6), so 616 is the answer.
- When trying to figure out a percentage of a number, try reversing the percentage number. What’s 18% of 50? Reverse to 50% of 18. 1/2 of 18 is 9. 18% of 50 = 9. 4% of 75 is the same as 75% of 4 which is 3/4 of 4 = 3. 4% of 75 = 3.
- Here’s a party trick: Pick any number between 1 and 9. Now multiply that number by 9. Now add the digits together. The answer will always be…9!
- Finally, here’s a practical trick that helps with your finances. It’s the Rule of 72. If you want to know how many years it will take to double your money at any fixed interest rate, just divide 72 by your interest rate number. (10% interest rate – 72 divided by 10 = 7.2 years. 3% interest rate – 72 divided by 3 = 24 years).
Playing around with numbers is fun and good for your brain, even if you aren’t as mentally quick as you used to be. Have some fun with numbers and your brain will thank you.
Fun fact: The longest mathematical equation is the solution to the Boolean Pythagorean Triples problem (you know the one 😊). The proof is 200 terabytes in size, and it took a supercomputer to generate. A single terabyte is “one million million.”
