Adding And Subtracting Could Be Easier If You Just Change Directions

Going left to right works just as well, and it might even be easier.


Dr. Katie Spalding

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory.

Freelance Writer

An apple on some books with some maths around it
You idiot, ALL this math is left to right! Image: ampcool/Shutterstock

Most of us, whether we like it or not, spend about twelve years minimum studying mathematics – learning how to recognize numbers, add them together and subtract one from another, multiply and raise powers, all that kind of stuff. Let’s face it, most of us have forgotten a whole lot of it a few years later.

Lucky for us, we live in an age of social media. While TikTok, for example, does admittedly sometimes result in accidental war crimes or thousands of scientific studies getting trashed, it can also have more wholesome, math-based uses – and there’s one new video you may have seen that fits perfectly into that latter category.


“Adding left to right is really underrated, in my opinion,” says Howie Hua in a recent viral TikTok video. He’s a lecturer at California State University, Fresno, where he teaches mathematics to future elementary school teachers, Upworthy reports – and he’s also an online math guru, with hundreds of videos filled with hints and tips for taking on the queen of the sciences.

But what does “adding left to right” mean? Well, let’s take the example Hua himself uses: 245 + 567. If you were set this to solve in school, you’d likely write it out like this:

Image credit: IFLScience


Then you would start adding: units to units, carrying any tens, then tens to tens, carrying any hundreds, and finally, hundreds to hundreds. 

Image credit: IFLScience


Hua does it in the opposite order.

“But wait!” we hear you cry. “You can’t do it that way! Mrs Grunderwald from fifth grade would give me a paddlin’ if I ever attempted such a thing!”

Here’s the thing about math: you can do anything. So long as it’s logical, it doesn’t matter! There’s no right or wrong, and no “cheating” – it’s all about making your life as easy as possible. As if to prove this further, Hua also demonstrates how to subtract from left to right, too:

Not only is it perfectly possible, but it also kind of makes things a bit easier to visualize, don’t you think? Check out the rest of his tips at his TikTok, Twitter, and YouTube.

Now, if he could just get started on solving the Riemann hypothesis from left to right, that’d be great.

H/T Upworthy


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