Math professor shows how adding and subtracting left to right is actually easier and faster
Mind. Blown.

Howie Hua shares helpful math tips and tricks on social media.
Math is weird.
On the one hand, it's consistent—the solutions to basic math problems are the same in every country in the world. On the other hand, there are multiple strategies to get to those solutions, and it seems like people are still coming up with new ones (much to the chagrin of parents whose kids need help with homework using methods they've never learned).
Math professor Howie Hua shares math strategies that make math easier on social media, and his videos are fascinating. Hua, who teaches math to future elementary school teachers at Fresno State, demonstrates all kinds of mental math tricks that feel like magic when you try them.
For instance, Hua has two videos showing how easy and quick it is to add multidigit numbers left to right instead of right to left, and it's genuinely mind-blowing.
Check out how he explains why adding left to right is "underrated."
\u201cNew TikTok video: Adding left to right is underrated\u201d— Howie Hua (@Howie Hua) 1665353677
OK, seriously. That is way easier to do in your head. It's basically putting the numbers into expanded form and adding them, which makes it easier to visualize.
Adding this way makes sense, but subtracting is a bit more complicated, right?
Wrong, apparently. Watch Hua work his math sorcery subtracting two and three-digit numbers.
@howie_hua Did you know you can subtract left to right? #math #mathematics #mathtok #maths #teachersoftiktok #teacher #mathtricks #mathtrick
Holy moly. That's faster than the right-to-left, borrow-from-the-next-column method, isn't it? And again, so much easier to visualize what's actually happening, though I don't know if I could fully do this in my head like I could with the left-to-right addition.
Hua recently shared another cool subtraction trick for problems with minuends that have a lot of zeroes. (The minuend is the first number in a subtraction problem. Don't be too impressed. I had to look it up.)
Check this out:
@howie_hua An underrated subtraction strategy #math #mathematics #mathtok #maths #teachersoftiktok #teacher #mathtricks #mathtrick
So simple, so time-saving and so something I would never have figured out on my own.
These tips and tricks might come in handy for anyone, but they're especially useful for kids who are having to do these kinds of math problems at school all the time. Even if they're supposed to solve the problem with a different strategy, these methods can be a quick way to check their answers.
Anything that makes math easier, I say. You can watch Hua's videos on TikTok, YouTube and Twitter.
This article originally appeared on 10.12.22
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There's a reason why some people can perfectly copy accents, and others can't
Turns out, there's a neurodivergent link.
A woman in black long sleeve shirt stands in front of mirror.
Have you ever had that friend who goes on vacation for four days to London and comes back with a full-on Queen's English posh accent? "Oooh I left my brolly in the loo," they say, and you respond, "But you're from Colorado!" Well, there are reasons they (and many of us) do that, and usually it's on a pretty subconscious level.
It's called "accent mirroring," and it's actually quite common with people who are neurodivergent, particularly those with ADHD (Attention Deficit Hyperactivity Disorder). According Neurolaunch, the self-described "Free Mental Health Library," "Accent mirroring, also known as accent adaptation or phonetic convergence, is the tendency to unconsciously adopt the accent or speech patterns of those around us. This linguistic chameleon effect is not unique to individuals with ADHD, but it appears to be more pronounced and frequent in this population."
Essentially, when people have conversations, we're constantly "scanning" for information—not just the words we're absorbing, but the inflection and tone. "When we hear an accent, our brains automatically analyze and categorize the phonetic features, prosody, and intonation patterns," writes Neurolaunch. For most, this does result in copying the accent of the person with whom we're speaking. But those with ADHD might be more sensitive to auditory cues. This, "coupled with a reduced ability to filter out or inhibit the impulse to mimic…could potentially explain the increased tendency for accent mirroring."
While the article explains further research is needed, they distinctly state that, "Accent mirroring in individuals with ADHD often manifests as an unconscious mimicry of accents in social situations. This can range from subtle shifts in pronunciation to more noticeable changes in intonation and speech rhythm. For example, a person with ADHD might find themselves unconsciously adopting a Southern drawl when conversing with someone from Texas, even if they’ve never lived in the South themselves."
People are having their say online. On the subreddit r/ADHDWomen, a thread began: "Taking on accents is an ADHD thing?" The OP shares, "My whole life, I've picked up accents. I, myself, never noticed, but everyone around me would be like, 'Why are you talking like that??' It could be after I watched a show or movie with an accent or after I've traveled somewhere with a different accent than my 'normal.'
They continue, "Apparently, I pick it up fast, but it fades out slowly. Today... I'm scrolling Instagram, I watch a reel from a comedian couple (Darcy and Jeremy. IYKYK) about how Darcy (ADHD) picks up accents everywhere they go. It's called ADHD Mirroring??? And it's another way of masking."
(The OP is referring to Darcy Michaels and his husband Jeremy Baer, who are both touring comedians based in Canada.)
Hundreds of people on the Reddit thread alone seem to relate. One comments, "Omfg I've done this my whole life; I'll even pick up on the pauses/spaces when I'm talking to someone who is ESL—but English is my first language lol."
Sometimes, it can be a real issue for those around the chameleon. "I accidentally mimicked a waitress's weird laugh one time. As soon as she was out of earshot, my family started to reprimand me, but I was already like 'oh my god I don’t know why I did that, I feel so bad.'"
Many commenters on TikTok were shocked to find out this can be a sign of ADHD. One jokes, "Omg, yes, at a store the cashier was talking to me and she was French. She's like 'Oh are you French too? No, I'm not lol. I'm very east coast Canada."
And some people just embrace it and make it work for them. "I mirror their words or phrase! I’m 30. I realized I start calling everyone sweetie cause my manager does & I work at coffee shop."