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- REUTERS/Vasily Fedosenko

- Math is hard – but sometimes it’s so hard, even parents are stumped when trying to help their children with their homework.
- Sometimes, equations that stumped parents and the internet are just plain wrong.

Homework is designed to challenge students, or, at the very least, reinforce what they learned during the school day. But sometimes these questions go a little too far in terms of difficulty (or they’re just plain wrong), forcing confused parents to ask the internet for help.

Check out these children’s homework questions that even adults couldn’t figure out without a little help from the worldwide web.

### First graders were expected to solve this problem in 20 seconds.

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- Puzzlersworld.com

This problem has been around for a while, but recently resurfaced on an elementary school entrance exam in Hong Kong. Apparently, six year olds were expected to know the answer in 20 seconds or less.

There’s something fun about this math problem – it requires no math! Just turn the question upside down, and you’ll see that it’s just a simple number sequence, with the answer being 87.

### Parents are split between two answers on this question for second graders.

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- MindYourDecisions/YouTube

A UK mom tweeted this math problem in a since-deleted tweet saying “Have you seen this one? Year 2!!” It was then picked up by a Facebook page called Parents Against Primary Testing and media outlets like The Huffington Post.

Calculating the answer is simpler than it seems: 19 people getting off the train can be represented by -19, and 17 people getting on the train as +17.

-19 + 17 = 2, meaning that there was a net loss of two people. If there are 63 people on the train now, that means there were 65 to begin with.

That said, many are convinced the answer is 46.

Here’s a full explanation of the answer.

### This homework question for third graders is simply too ambiguous.

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- L8asUsual/Reddit

This is *way* too vague to be an acceptable question. All the problem states is that Janell lost “some” of her marbles. There is literally no way to know how many she has now.

When the problem hit Reddit, a wealth of answers came flooding in, including “some,” “15 – n {n ∈ ℤ | 1<n<15},” and “15 – n” all of which seem incorrect or too complicated for eight year olds.

The simplest answer is < 15, but even that is a little abstract for a third grader.

### This type of problem is known as a petite circle sum, and this one is meant for first graders.

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- ALMONDSHELL/HARDWAREZONE

This question appeared on Twitter, where a user said it was for first graders in Singapore.

This type of question is known as a petite circle sum. The numbers in the four sections should be equal to the sum of the three numbers in the circles touching that section. Numbers in circles can’t be higher than a nine, and only used once.

Some people said there was a typo and that the two should be a 20, while others claimed they had figured it out with the numbers given. While definitely tough for a first grader, an explanation that circled the internet supports the typo theory.

### Known as “Cheryl’s Birthday,” this is one of the most famous homework questions in the world.

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- Kenneth Kong/Facebook

Kenneth Kong, a television host in Singapore, shared a photo of this 9th grade-level math question in a since-deleted Facebook post, which was shared nearly 6,000 times.

In the logic puzzle, Cheryl gives her friends Albert and Bernard different clues as to when her birthday is out of a selection of dates. She tells Albert only the day and Bernard only the month of her birthday.

By making a table of the dates and using the process of elimination, one can determine that Cheryl’s birthday is July 16.

It was later revealed that this problem wasn’t a regular test question used in Singapore classrooms. It was actually used in a contest as part of the Singapore and Asian Schools Math Olympiad (SASMO).

The New York Times published a detailed explanation of the solution, which you can read here.

### The wording of this question is confusing.

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- @BrianWithCheese/Twitter

This picture was posted on Reddit, with the caption “The American education system.”

There are two things that are confusing about this question. One, the wording implies that it *is *possible for Marty to eat more than Luis. Two, it’s never specified whether the pizzas are the same size or not, so the student is technically right. Thus, the teacher is wrong, because there *are *situations where it is possible.

### This math question in Vietnam isn’t that difficult, but extremely time consuming.

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- VN Express

The challenge: use each digit 1-9 only once to fill in the snake and make the equation equal 66 (colons are division signs).

According to VNEXPRESS, this puzzle is meant for third graders. There’s no trick or complicated math necessary – finding the correct configuration of numbers comes down to trial and error and process of elimination.

A comment thread on a Guardian article has over 1,000 comments from people trying to figure out how to solve this question.

Eventually, there was an post explaining how to solve the puzzle, which involved a *lot *of trial and error.

### This problem caused controversy.

After this tweet unexpectedly went viral, people were quick to assume that there had been some sort of mistake. If it takes 120 people to play a 40-minute song, how long would it take 60 people to play the same song?

If you said 80 minutes, you’re among the majority, but still wrong. A song is 40 minutes no matter how many people are playing it.

The original author of the question explained that it was just a trick question to keep her students on their toes.

### Not even kindergarten students are safe from impossible homework questions.

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- Royce Winnick/Facebook

Since the first three answers start with a “t,” wouldn’t it make sense for the last picture to also start with a “t?” Maybe, but what if there’s no t-word that makes sense? Royce Winnick posted this picture on Facebook to ask for help with her daughter’s homework, and got suggestions like “twins,” “twabbit,”and “this was an error.”

The real answer? Vet, which is a stretch, and also doesn’t start with a t.

### A family had to ask Facebook for help with their first grader’s homework.

To put it simply: if a problem is too complicated for a parent to figure out, it’s too hard for a first grader.

The question is essentially algebra (which is normally taught at a much older age), and requires substituting the letters for numbers. The answer is J/14, in case you were still confused.

### Apparently, 80% of kids were able to answer this brainteaser, which has a geographical element.

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- National Geographic / YouTube

National Geographic used this puzzle in their show “Brain Games.” They also stated that 80% of kids were able to answer which way the bus was driving immediately.

Still stumped? It depends on where in the world you are – in the UK, you drive on the left side of the road, so the bus must be traveling towards the right (a bus’ door always points to the curb). On the other hand, if you live almost anywhere else, the bus is heading to the left.

### A typo made this question impossible to answer.

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- Mothership.sg/Facebook

Chalk this one up to human error. This word puzzle simply doesn’t make any sense. The logical answer would be excited, but the right letters aren’t an option.

The typo didn’t stop people from trying to figure out what the right answer could be.

### These two answers both seem correct, but one is “more” correct.

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- Cloakenn/Imgur

The first question asks the student to calculate 5 x 3 using repeated addition. The student wrote 5 + 5 + 5 = 15, and was marked wrong, with the teacher writing in the “correct” solution of 3 + 3 + 3 + 3 + 3 = 15.

The second question prompts the student to calculate 4 x 6 using an array. The student drew an array with six rows and four columns, getting the answer that 4 x 6 = 24. The teacher marked the question wrong again and drew in a nearly identical array of four rows and six columns.

“The idea that a student should be punished for recognizing and applying the fundamental truth of commutative multiplication in service of drilling in a completely arbitrary convention that they can easily learn when they need it 10 years later strikes me as borderline insane,” Andy Kiersz of Business Insider wrote.

Read the full explanation here.

### When an 11-year-old girl brought this home, even her mom couldn’t help her.

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- Facebook/Springfield News

When a mom took to Facebook to ask for help/complain about the difficulty of this problem, someone commented “Can someone give me the answer. I have a headache,” and most people agreed.

Even with the solution (2/8 + 2/3 = 12/48 + 32/48 = 44/48 = 11/12), it’s still a confusing problem.

### Grammar can be tricky for everyone, not just kids.

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- Kids R Simple/Facebook

If you think that the right answer to all of these questions is option three, you’re not alone. However, it’s actually option one for all of them.

This is because of the subject-verb agreement rule – a singular noun (Mark, Jacob, the trial) should be followed by a singular verb.

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