40+ Most Embarrassing Math Fails Caught Online

We know a lot of people have trouble automatically calculating the proper conversions for things like teaspoons, cups, and gallons. But, the internet is a very useful tool, so there’s no reason to so confidently make a wrong statement like this online.

A quick internet search would reveal that a quarter of a cup is not 10% of a gallon. There are 16 cups in a gallon, just for your reference. It took two seconds of internet searching to find that out, so there’s no excuse for this post.

Figuring out how old someone is when you know what year it is and what year they were born in is generally as easy as doing subtraction, and yet, somehow there are people out there who still manage to mess things up — even if it’s only by a small number.

Admittedly, maybe this article was updated to the present year (at that point), and they just forgot to update her age along with it. But, since they forgot to, it’s still a math fail for the internet to laugh at.

March 14th is often referred to as “Pi Day,” making it a sort of mini-holiday for pizza lovers and pizza restaurants. Usually, pizza joints offer some sort of impressive deal on Pi Day, which often involves the number 3.14.

It’s possible that this pizza joint wasn’t actually intending to offer a deal for that price, but it seems a little odd that they got as close as $3.33 and didn’t just go all the way. But, we can give them the benefit of the doubt.

Generally speaking, the idea of being able to buy things in bulk is to be able to get the product for cheaper than if you bought them individually. However, this restaurant seems to be missing that point, considering that you would have to pay more to buy four packs of three rangoons than if you bought a pack of 12.

Obviously, this doesn’t make any sense, as you could buy the same amount of food for less money if you just bought it in smaller increments. They definitely didn’t think that through.

25 meters of tape (or whatever this is) seems like it would be pretty useful in most cases, and we supposed that it might be a good deal to get all of it for $330. On the other hand, the price per meter is clearly off — $132 per meter would be absurdly expensive!

Clearly, this store misplaced a decimal, at which point this sign would make a lot more sense. We suppose this could just be a small clerical error, rather than a huge math fail.

When you offer a deal regarding a customer buying two of a product instead of one, the incentive is to make the two products bought as a pair cost less than if you bought them individually. However, this gas station seems to have missed the point completely.

Sure, they are only off by two cents, but even so, what’s the point of offering a two-purchase deal if it comes out to about the same as the purchase of two drinks individually? That’s pointless.

Anyone who likes Dr. Pepper knows that it allegedly contains 23 different flavors. But, holding two cans of Dr. Pepper doesn’t mean you’re now in possession of 46 flavors. After all, the three cans are identical in flavor, so you can’t count them as different.

We get that this guy was trying to go for a joke, but no matter how many Dr.Peppers you’re in possession of, you’ll always only be in possession of 23 flavors. You can have more of the same flavor, but that’s all.

Missing a zero makes all the difference between a hundred years and a thousand. Making a silly mistake like that makes you look pretty silly — anyone with common sense could tell you that anyone alive right now isn’t going to live until the year 3000.

The notion this person put forward is artistic and all, but it unfortunately falls apart when they can’t tell the difference between 78 years and 978 years. There’s just a bit of a difference there.

So, a bottle claims to contain 15 calories total, broken up into three servings. But, it also claims there are zero calories per serving. Something definitely seems wrong with that math, doesn’t it? Well, there’s actually something more sinister involved.

In the US, companies don’t have to list ingredients that fall below a certain amount. Because a serving has less than the amount required to be divulged to the public, the company can say “zero” to try and mislead people, as long as they list the full calorie count elsewhere.

As far as percentages are concerned, what constitutes a “majority” depends on how many categories you’re breaking that percentage into. In this situation, 40% would not seem to be the majority, which this headline so clearly states.

It seems like a math fail, but we’ll admit that perhaps there were three categories here, of which 40% was the largest. Still, what was the third option? Was it “yes, no,” and “don’t care”? They really should have offered more information.

It’s very true that little things add up over time. However, not quite in the way this post is trying to claim. 20 minutes, 365 days a year, equals 7300 minutes. Divide that by 60 minutes (an hour), and you get approximately 121 and a half hours.

Don’t get us wrong — that’s still fairly impressive, but it’s a far cry from 1000 hours. Unfortunately, a math mistake like this can go a long way in ripping your nice sentiment apart. Always double-check your math!

Open 24/7 means that a location is open 24 hours a day, seven days a week. So 24/5 should mean that a place is open 24 hours a day, five days a week, right? Well, that’s clearly not how this Planet Fitness did the math.

Apparently, their logic is that they’re open from 5AM to 10PM (17 hours) five days a week, and 12 hours on two days a week. That’s 109 hours a week, which they seem to have divided by 24 to get a number close to five (it’s actually 4.54). Kind of crazy.

The older generation will often complain about the new ways math is taught these days, but in some cases, the way people use math really is mind-boggling. Apparently, New Cuyama believes its total population is determined by their population, plus their elevation above sea level, plus their year of establishment.

Or maybe they don’t, but they don’t exactly specify what the sum is supposed to represent, since it’s just the sum of a bunch of unrelated statistics. Maybe we just don’t get the joke?

We’re sure that some people just add numbers in their head without really paying attention to what they’re doing. Whoever made this post clearly did a “born in 2010 + 12 years old” equation, but the fact that they didn’t realize their mistake before typing it all out and posting it is a little sad.

This is why we’re a firm believer in everyone double-checking what they’re going to post online before they actually do it. No need to make a fool of yourself with math.

Speaking of people who don’t know how simple and easy it is to subtract someone’s birth date from the current year, we have this fiasco. Other than just being outright off by three years, we’re not sure what kind of math they were trying to do here.

Were they trying to factor in leap years or something? Or can they just not count? They may no longer be a kid, but it seems like they still need to go back to primary school.

Alright, we’re going to cut this one some slack, since the person who can’t do math properly appears to be 10 years old. We can give them a slight pass for that (although honestly, basic addition should be very doable for a 10-year-old). Still, we’re going to put him on this list.

The sad part is, this amount of confidence in being wrong is usually something adults do even better than kids. Most of the people on this list are adults or companies run by adults. Yikes.

We’re not sure what it is about people and their inability to properly divide with any number that goes into the millions, but there are a lot of them out there. How many times does 6.6 million go into 21 million? 3.18, not 3.18 million.

But hey, don’t get us wrong — depending on what type of penguins we’re talking about, Ireland could have a serious problem on its hands if a penguin invasion occurs. Have you seen what those things get up to out there in Antarctica?

It appears that a lot of people don’t really get how percent increases work. If you have half a gallon and increase it by 50%, you’re increasing it by half of half a gallon. In order to double it, you have to increase the content by 100%.

But admittedly, we get why this is confusing to some people. They view half a gallon as 50% of a gallon, so adding another 50% should make a whole gallon, right? Yeah, well, it’s not as simple as all that.

Don’t get us wrong, passive income is great. But if you had to choose between one million dollars at once, or only $50 a month for the rest of your life, option A is clearly the better option. $50 a month is only $600 a year.

In other words, it would take approximately 1667 years to make one million dollars with that level of passive income. Needless to say, taking one million upfront would be the much smarter choice. Passive income is great, but this example is not.

Here we have another example that’s terrible in two ways. While the initial poster is right in saying that 500,000 is a statistically insignificant number compared to 300 million. But, we’re talking about human lives here, and it’s pretty terrible to look at it that way.

On the other hand, the responder honestly believes that 1/6 of the population of America died in this scenario, clearly mistaking three million for 300 million. There’s a pretty significant difference in those two numbers. Besides, 1/6 casualties would be ludicrous.

Everything that could be wrong with these prices, is. Even if you weren’t that hungry, why would you spend more on four nuggets if you could spend less and get eight? And if you wanted to get 20 nuggets by buying packs of four, you’d be spending way more than buying the straight 20.

Of course, there’s usually some logic to making larger batches a better deal so people will be incentivized to buy, but having four nuggets cost outright more than eight definitely seems like a math fail.

Elon Musk has been the target of much disdain by people who believe his money should be used for more charitable causes. We aren’t saying we disagree with them, but if you’re going to make such an argument, the least you could do is offer correct math.

Needless to say, this person seems very confused as to how many “one billions” go into 188 billion. That, or they believe the population of Earth is eight people. Both notions are pretty alarming.

On one hand, we really want to give this person the benefit of the doubt. Maybe they were just trolling? Unfortunately, we can’t say that with certainty, because there really are some stupid people out there.

If they’re being serious, they seemed to have missed the most basic way of calculating one’s age somewhere in grade school. If they’re joking, this is actually pretty clever satire. It’s just a shame we can’t know for sure which one it actually is.

We all wish that some ultra billionaire could solve all of our financial problems by handing out a billion dollars or more, but the notion that anyone on Earth has enough money to provide billions to every human alive is pretty crazy.

Thankfully, someone was around to point out all of the huge math problems on display here, but it’s shocking that a professor (if he really is one) made such a glaring error, no matter what his area of expertise actually is.

Anyone who remembers grade school math also remembers that anything times 0 is zero. After all, if you have zero bundles of 10 apples, you still have zero apples. This guy apparently thinks that, as long as you flip the numbers around, this is not the case.

Unfortunately, that only works with subtraction and division. Flipping numbers around changes nothing about basic multiplication. He missed the joke, the lesson, and any sign of common sense or intellect.

Imagine getting upset with a restaurant for giving you back more than you’re actually owed just because you can’t do math. This woman handed off a pretty large bill for a restaurant to split, and said restaurant decided to just let her keep the change.

Pretty nice on their part, since even small amounts of money stack up over time. It’s just too bad that the person they did this nice thing for has no idea how to count. Maybe they won’t be so nice next time.

It’s one thing when you can’t do basic math, but it’s even worse when you don’t know anything about anatomy either, especially when it’s your anatomy that’s in question. The idea that the amount of time you spend pregnant is multiplicative with the number of babies you’re carrying… wow.

Really, have you ever heard of anyone being pregnant for 27 months straight? You’d think even the dimmest bulb in the shed would realize that such a notion is ridiculous. But, we might be giving her too much credit.

So, it’s actually quite normal for a restaurant to offer the same amount of food at a lower price if you buy in bulk. Technically, if you wouldn’t have spent that much money otherwise, they’re making more money than they would have.

The problem here is that the four-piece meal is always the right option. You can get it for less than if you bought two two-piece meals, but also buy a couple of four-piece meals for less than the single eight-piece meal. There’s no reason to ever buy the eight-piece.

Aside from the incredibly dubious statement that greed doesn’t exist, this guy also can’t do math. If you spend a buck to make something, then make a 10% profit, that means you only sold the item for $1.10 — earning 10 cents in profit. He seems to have meant 100% profit.

Making all of this worse is his confidence in being correct. He even goes on to say that it’s “basic math,” which is pretty hilarious when you consider the situation. Fun, indeed.

Ignoring that this pizza joint somehow “ran out” of nine-inch pizzas (they must use frozen dough?), we’re not sure if this guy is just crotchety or doesn’t know how to do math. He really is getting extra pizza in this scenario.

We’re just assuming that he’s so bad at math that he doesn’t realize this. After all, who in their right mind would complain about getting more pizza than they actually paid for? You can’t possibly go wrong with that, so mathematical incompetence is the only explanation.

Many students — whether or not they love math — hate fractions, mostly because you have to put up with seemingly asinine equations that are unnecessarily complicated. However, this frustration with fractions is unwarranted in this scenario. Almost everybody can tell you that three of 1/3 equals one (well, virtually a one).

We’re not sure how somebody got this wrong on the sign being displayed here. They either have no idea what 1/3 of a mile actually is or added an extra number to the equation. It’s sad, either way.

We don’t know what these two individuals were actually arguing about, but it’s not hard to see which one of them is incapable of proper math, based on their exemplary proof of incompetence on display. Sure, all they did was miss a decimal placement, but that’s a big deal.

Remember, kids — an error as small as a decimal being properly placed can turn a correct answer into an example of buffoonery. Also, the internet can calculate this stuff for you, so double-check before posting so confidently.

There’s a time to let a good joke exist without pigeonholing it, but if a joke is dependent on math to work, and the math being used is wrong, well… it’s not a very good joke in that case, is it? This is an example of one such joke.

Yeah, maybe the fraction guy is a party pooper. But, he’s right, although the joke wasn’t really that good anyway. It sounded like something that would have been really popular as a Facebook meme.

We’re honestly not sure what to say about this post. We don’t even know what kind of math this person is actually trying to do, from a logical standpoint. All we know is that, in 2021, they somehow deduced that 2019 was seven years prior.

We’re not sure why any math was required considering that this assessment just doesn’t make sense at all, but we get the feeling that this guy didn’t really know why any math was required either. That’s usually how you get nonsense like this.

We suppose in a manner of speaking, you could view 25 as halfway to 30, if you were considering 20 as the starting point. But, while we can see a certain logic to it, it’s still wrong. 25 is definitely not halfway to 30.

Still, we kind of get what he was going for here. Maybe they consider you to enter a new stage of life every decade? Either way, he probably wasn’t actually thinking about it that hard when he said it.

We suppose you could say this is less of a math fail and more of someone just not paying attention to what they were typing, but it’s still funny to see a website claim that the Realm of Denmark is bigger than the whole of South America.

Bonus points for literally telling everyone that South America is much larger in landmass only to claim that Denmark is bigger afterwards. Maybe someone just didn’t have enough coffee that morning.

Honestly, failing basic math in public is one of the quickest ways to just completely neuter your credibility. Always make sure you know what you’re talking about before making a post like this. Spoiler alert — you can’t just add two percentages from two different categories together in this fashion.

Obviously, these percentages don’t represent the entire population of the country, and even if they did, the respective percentages are only representing either women or men as a group. There’s a lot wrong with this statement, is what we’re saying.

Speaking of people who just apparently have no idea how percentages work, we have this individual who has completely misunderstood the point of a statistics post. These percentages aren’t mutually exclusive, meaning they can overlap.

Clearly, that’s a point that was missed by this guy, who erroneously assumed otherwise. Turns out that people can be both women and of a certain ethnicity, and thus be part of multiple categories. Who knew?

While it’s true that different objects have different weights and masses, weight itself does not change based on what it’s comprised of. One ton of feathers weighs the exact same amount as one ton of diamonds. It would just take a lot more feathers to reach that weight.

This concept was clearly lost on the individual who made this post. Even worse is the fact that weight has nothing to do with why body armor isn’t made out of diamonds.

Pretty much anything can be divided by two, even if the result isn’t a clean, whole number. Not only does this person not know this, they apparently believe 190 is one of those numbers that can be cleanly divided by two. Maybe they think it’s an odd number?

Turns out that 50% of 190 is a very simple 95. And remember, if you say something stupid and add emojis to it, you’re far more likely to be judged for your terrible math skills.

Some people are of the mind that being half of someone’s age at one point means you’ll always be half their age. Needless to say, this is not actually true, considering that being at the exact halfway mark to someone else is not linear at all.

But hey, maybe this guy is trolling. It kind of has that vibe. It’s just a shame that we can’t actually say that with any certainty — because, well, you’ve seen this list now. You know how stupid some people are.

Did you know that miles per hour is actually a concrete number that you can easily do basic math with? Did you also know that sleeping does not subtract from the total number of hours in the day? Apparently, this guy did not know either of those things.

To drive 2000 miles in one day, you would actually have to ride at approximately 84 miles an hour for 24 hours straight, from start to finish. We suppose that’s technically possible, but it realistically isn’t.

OK, so trying to diminish the tragedy of a plane crash in which 3000 people died is messed up in and of itself, but it’s not a math fail. The math fail here is the responder, who evidently believes that less than 3000 people died in World War II.

Somewhere between 70 and 85 million people died due to the events of World War II. That was about 3% of the human population of Earth in 1940. Yeah, that’s definitely a little bit more than 3000.