retirement lifestyle

Retirement planning forces us to make many decisions, as well as calculations. And while a professional can help you with those, it can also help to sharpen up your math skills. Calculating percentages and interest rates off the cuff this isn’t difficult, but it can be intimidating without pen and paper. After all, you haven’t taken a math test in decades! But, maintaining your calculation skills is an important part of keeping your brain sharp in retirement.

Calculating Percentages

If something is 25% off, for example, think of that as a quarter of the price. If something costs $60 and is 25% off, divide 60 by 4, which is 15. Then subtract that quarter from the overall price, and you’re left with $45. If the percentage isn’t as simple as a quarter or half, like a 15% restaurant tip, there’s another technique. Figure out what 10% of the amount is by moving the decimal point one to the left. For example, if your bill is $40, 10% of that is $4. Then take half of that amount ($2), and add it to the 10% amount ($4) to get a 15% tip of $6.

Rule of 72

There is an easy way to estimate how long it will take an investment to double. If you know what the interest rate will be, take 72 and divide it by that rate. For example, if your investment earns an annual interest rate of 10%, divide 72 by 10 to get 7.2 years. This is a close estimate of how long it could potentially take that money to double.

Mental Workouts

Frequent mental workouts are an important part of an active retirement. It’s also the best time, since you’ll have more free time to devote to subject areas that interest you. Never stop learning or challenging yourself to think critically, no matter how old you are. Whether you enjoy crossword puzzles, Sodoku, reading or learning a bit of another language before taking a trip to a foreign country, staying sharp is critical in retirement.

At Epstein & White, we want to empower you with knowledge, which is why we’ve created comprehensive guides on a myriad of retirement topics. We can provide you with more information on whatever subject you need – tax minimization strategies, healthcare planning, retirement investing, Social Security maximization strategies, and more. We would love to have a conversation, so sign up for a complimentary financial review.


Epstein & White is a tradename. All services provided by Epstein & White investment professionals are provided in their individual capacities as investment adviser representatives of Mercer Global Advisors Inc. (“Mercer Advisors”), an SEC registered investment adviser principally located in Denver, Colorado, with various branch offices throughout the United States doing business under different tradenames, including Epstein & White. Information contained herein is for informational and illustrative purposes only and general in nature. It should not be considered investment advice or a recommendation to buy or sell any type of securities or insurance products and no investment decision should be made based solely on any information provided herein. Investing involves risk, including the possible loss of principal. Diversification and asset allocation does not ensure a profit or guarantee against loss. We provide this information with the understanding that we are not engaged in rendering legal, accounting, or tax services. We recommend that all investors seek out the services of competent professionals in any of the aforementioned areas.