Watching kids do lightning fast mental math is both mesmerizing and mind-blowing

Their finger twitching looks random, but WOW is it impressive.

Digamarthi Sri Ramakanth/Wikimedia Commons

2003 UCMAS National Abacus & Mental Arithmetic Competition

In the age of calculators and smartphones, it's become less necessary to do math in your head than it used to be, but that doesn't mean mental math is useless. Knowing how to calculate in your head can be handy, and if you're lucky enough to learn mental abacus skills from a young age, it can be wicked fast as well.

Video of students demonstrating how quickly they can calculate numbers in their head are blowing people's minds, as the method is completely foreign for many of us. The use of a physical abacus isn't generally taught in the United States, other than perhaps a basic introduction to how it works. But precious few of us ever get to see how the ancient counter gets used for mental math.

The concept is simple and can be taught from a young age, but it takes a bit of time and practice to perfect. Watch what it looks like for basic addition and subtraction at lightning speed, though:

If you don't know what they're doing, it looks like students are just randomly flicking their fingers and wrists. But they are actually envisioning the abacus while they move their fingers, as if they were actually using one.

There are various methods of finger calculations that make use of abacus concepts. Watch another method that uses both hands in action:

Even very young children can calculate large sums very quickly using these abacus-based mental math methods. Watch these little superstars add two-digit to four-digit numbers like it's nothing.

How do they do it?

Much of the skill here requires a solid understanding of how an abacus is used to calculate and lots of practice with the physical movements of calculating with it. That's not exactly simple to explain, as it take a couple of years of practice using an abacus—for these mental calculations, specifically the Japanese soroban abacus—to gain the skills needed to be able to calculate quickly. BBC Global shares how such practices are taught in Japan, not only for mental math but for overall cognitive memory:

Abacus mental math programs online recommend learning it between the ages of 5 to 13. It is possible to learn at older ages, but it might take longer to master compared to younger students.

But if there's a finger method you want to try for addition and subtraction up to 99, one that's simple and quick to learn is called chisanbop, in which ones are counted on one hand and 10s are counted on the other. Here's an explainer video that shows how it works:


Most of us carry calculators around in our pockets with us at all time, so such practices may feel like a waste of time. But learning new skills that tax our brain is like a workout for our mind, so it's not a bad idea to give things like this a spin. Even if we don't learn to calculate large numbers in the blink of an eye, we can at least exercise our mental muscles to keep our brains healthier. And who knows, maybe we'll get a party trick or two out of it as well.

Hexagons are the best of all polygons.

"What's your favorite shape?" is generally a question we ask 5-year-olds, not grown adults. But maybe if we put it into more advanced terms—"What's the best polygon?"—we'd be compelled to give it some genuine thought.

Since there's an entire field of math dedicated to triangles, that might seem like a logical answer. But, most human-made things around us are made up of rectangles, so maybe they're the best. Then again, there are much more interesting quadrilaterals than squares and rectangles (hey, rhombus!) in addition to pentagons, hexagons, heptagons (which I don't think I've ever even seen), octagons, nonagons—so many "gons" to choose from.

As it turns out, there is an answer to this question—at least according to popular YouTube creator CGP Grey.

The answer? Hexagons. Who knew, right?

If you have doubts that the six-sided shape deserves the title of "best," CGP Grey's video might change your mind.

In it, we see how bees use hexagons to make honeycomb. That's not by accident; it's because hexagons are actually the most efficient shape for tiling. It's the same reason bees' eyes are made up of tons of tiny hexagons—and why the back of our eyes are too.

Snowflakes have six sides, which alone is reason enough for the hexagon to be the bestagon, but the reason they're six-sided is super cool. Saturn has a mysterious, humongous hexagon of gases the size of six Earths, which is weird but also super cool.

But that's just the peripheral stuff. There's a fundamental atomic reason why hexagons are the bestagons—strength and stability which allows hexagons to create the strongest atomic material in the universe.

And, of course, Settlers of Catan.

If you have doubts, let CGP Grey convince you. By the end, you'll have to at least admit that hexagons are pretty darn cool, even if you're partial to some other polygon.

Delores Spencer has been teaching math since 1954. When she retired from her Virginia school district 30 years ago, she started tutoring students and hasn't stopped. Now, at age 89, even in the midst of a global pandemic, Mrs. Spencer is still going strong.

Mrs. Spencer has kept up her teaching skills through her decades since retirement, even learning the new ways math gets taught. And when in-person tutoring got thwarted by COVID-19, she took it as an opportunity to reach more people through virtual tutoring.

Since last spring, Mrs. Spencer has provided math lessons online through her Math Lab on Facebook and YouTube. Each week, she posts a free, hour-long lesson on a particular math concept to help students and parents learn better.

"I just really wanted to help students get over that fear of math," Spencer said in a video interview with Good Morning America. "So many parents and students have fear of mathematics. And it really, it's beautiful."

She said she wants to reach people who need tutoring but can't afford it. "If I can find out what blocks you, then I can remove that block, and usually you don't need me anymore until you get to another block. And that's what real tutoring is about."

Watch this inspiring woman in action:

89-year-old math tutor's virtual lessons reach students around the world l GMAwww.youtube.com

Thank you, Mrs. Spencer, for showing us that we don't have to stop doing what we love just because we get older, and for continuing to share your gift of teaching with the world.

Fourteen-year-old Alaina Gassler had noticed her mother struggling with blind spots while driving their family's car. Though not even old enough to drive herself, the Pennsylvania middle schooler designed a system that uses a webcam to display obstacles blocking a driver's line of sight to make driving safer.

Last week, that design project earned Gassler the $25,000 Samueli Foundation Prize, the top award in the 2019 Broadcom MASTERS (Math, Applied Science, Technology, and Engineering for Rising Stars) competition.

"Congratulations to Alaina, whose project has the potential to decrease the number of automobile accidents by reducing blind spots," said Maya Ajmera, President and CEO of the Society for Science & the Public and Publisher of Science News. "With so many challenges in our world, Alaina and her fellow Broadcom MASTERS finalists make me optimistic. I am proud to lead an organization that is inspiring so many young people, especially girls, to continue to innovate."

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Indeed, Gassler wasn't the only girl to shine in the national contest. All five top awards were won by 14-year-old girls, with projects ranging from trapping invasive species to improving water filtration systems to designing bricks that could be used to build on Mars.

The five winners were chosen from 30 finalists selected from 2,348 applicants in 47 states by a panel of distinguished scientists, engineers and educators. This year, 60% of the finalists were female—a first for the competition. That's an encouraging sign for the STEM (Science Technology, Engineering, and Mathematics) field, in which women are still underrepresented.

"Congratulations to all our amazing finalists!" said Paula Golden, President of the Broadcom Foundation. "It is exciting to see so many young women scientists and engineers – 60% – in the competition this year. I believe that this bodes well for achieving greater gender equity in future STEM careers."

While the results of this competition are promising, research shows that it's not necessarily initial interest and involvement in STEM that's the problem—it's that women tend to slip out of the STEM career pipeline somewhere along the way. Nonetheless, a solid foundation in STEM and early achievements and accolades may encourage more girls to stick with their science and engineering pursuits.

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Congratulations to the top five winners:

The Samueli Foundation Prize: $25,000
Alaina Gassler,
Improving Automobile Safety by Removing Blindspots

Lemelson Award for Invention: $10,000
Rachel Bergey,
Spotted Lanternflies: Stick'em or Trick'em

Marconi/Samueli Award for Innovation: $10,000
Sidor Clare,
Bound and Bricked

Robert Wood Johnson Foundation Award for Health Advancement: $10,000
Alexis MacAvoy,
Designing Efficient, Low-Cost, Eco-Friendly Activated Carbon for Removal of Heavy Metals from Water

STEM Talent Award, sponsored by DoD STEM: $10,000
Lauren Ejiaga,
Ozone Depletion: How it Affects Us

What an inspiring lineup of young women working to make our lives better through science and technology. Though women still have an uphill climb to achieve gender parity in STEM fields, the future is looking bright in these kids' hands.