“What happened to carrying the one?” Dad’s math homework meltdown feels all too familiar
- Replies 0
If you’ve ever found yourself staring at your grandchild’s math homework and wondering if you accidentally picked up a textbook from another planet, you’re not alone.
In fact, you’re in good company—just ask Mark, a father from Lincolnshire, UK, who recently found himself in a full-blown existential crisis over his 7-year-old son’s math assignment.
Let’s set the scene: Mark, a self-confessed supporter of homework (despite his own childhood grumbles), was helping his son with a seemingly simple question about fractions on a number line.
The question read: “Eva is working out what fraction is shown on the number line. What mistake has Eva made?”
Next to it, a cheerful drawing of Eva declared, “The number line shows eighths.”
Mark, like many of us, took one look and thought, “Well, that seems right. There are eight segments, so eighths it is!”
But as he stared at the problem, doubt crept in. Was he missing something? Was this a trick question? Was he, as he put it, “losing his sanity?”
When in doubt, turn to the internet! Mark posted a photo of the homework to Reddit, hoping for a little clarity and maybe some commiseration.
The response was overwhelming—over 1,400 upvotes and a lively discussion that revealed the sneaky culprit behind his confusion: the infamous “fencepost error.”
The Fencepost Error: A Classic Math Trap
If you’ve never heard of the fencepost error, you’re not alone. It’s a classic math mistake that’s tripped up everyone from Roman architects to modern-day fencing contractors.
Here’s the gist: when you divide a line into segments, the number of segments is always one less than the number of points (or “posts”) marking them.
So, if you see eight marks on a number line, you actually have seven segments—meaning the line is divided into sevenths, not eighths.
As one social media user explained, “It’s called the fencepost error and it’s been written about for thousands of years. The Romans needed to know about this so they could work out how many pillars to put around a temple.”
Another chimed in, “As someone who sells fencing, I’m amazed at the amount of people who don’t realize they need that extra post. I never knew there was an actual term for it though, so thank you!”
Source: @kumquat_may / Reddit.
It’s a simple mistake, but one that’s easy to make—especially when you’re seven years old (or, let’s be honest, any age at all).
Why Is Math Homework So Tricky These Days?
Mark’s story is just the latest in a long line of parents and grandparents scratching their heads over elementary school math. And it’s not just about fenceposts and fractions.
The way math is taught has changed dramatically over the years, with a greater emphasis on understanding concepts rather than just memorizing formulas.
That’s a good thing in the long run, but it can make helping with homework a real challenge for those who learned math “the old-fashioned way.”
Also read: The math problem for kids that’s baffling grown-ups—Can you crack the code?
A 2013 study in The Journal of Experimental Education found that students in high-performing schools were spending more than three hours a night on homework, leading to increased stress and even health problems.
While homework can reinforce learning and build good study habits, it can also create confusion and frustration—especially when the instructions aren’t crystal clear.
But let’s not forget the humor. One commenter shared a story about a cleaner working from 8 to 12 o’clock, thinking it was four hours for four floors—only to realize it was actually five floors.
Another pointed out that dividing a sandwich for a math problem had stumped a 6-year-old girl (and, presumably, her parents too).
Read next: Think you're smarter than a 5-year-old? This kindergarten homework puzzle has stumped PhDs!
Have you ever been stumped by a child’s homework? Do you have a favorite “trick question” that caught you off guard? Or maybe you’ve got a tip for making sense of today’s math assignments? We’d love to hear your stories, your struggles, and your solutions!
In fact, you’re in good company—just ask Mark, a father from Lincolnshire, UK, who recently found himself in a full-blown existential crisis over his 7-year-old son’s math assignment.
Let’s set the scene: Mark, a self-confessed supporter of homework (despite his own childhood grumbles), was helping his son with a seemingly simple question about fractions on a number line.
The question read: “Eva is working out what fraction is shown on the number line. What mistake has Eva made?”
Next to it, a cheerful drawing of Eva declared, “The number line shows eighths.”
Mark, like many of us, took one look and thought, “Well, that seems right. There are eight segments, so eighths it is!”
A UK dad turned to social media for help after struggling with his 7-year-old son's math homework, which asked about a number line mistake involving fractions. Image source: @kumquat_may / Reddit.
But as he stared at the problem, doubt crept in. Was he missing something? Was this a trick question? Was he, as he put it, “losing his sanity?”
When in doubt, turn to the internet! Mark posted a photo of the homework to Reddit, hoping for a little clarity and maybe some commiseration.
The response was overwhelming—over 1,400 upvotes and a lively discussion that revealed the sneaky culprit behind his confusion: the infamous “fencepost error.”
The Fencepost Error: A Classic Math Trap
If you’ve never heard of the fencepost error, you’re not alone. It’s a classic math mistake that’s tripped up everyone from Roman architects to modern-day fencing contractors.
Here’s the gist: when you divide a line into segments, the number of segments is always one less than the number of points (or “posts”) marking them.
So, if you see eight marks on a number line, you actually have seven segments—meaning the line is divided into sevenths, not eighths.
As one social media user explained, “It’s called the fencepost error and it’s been written about for thousands of years. The Romans needed to know about this so they could work out how many pillars to put around a temple.”
Another chimed in, “As someone who sells fencing, I’m amazed at the amount of people who don’t realize they need that extra post. I never knew there was an actual term for it though, so thank you!”
Source: @kumquat_may / Reddit.
It’s a simple mistake, but one that’s easy to make—especially when you’re seven years old (or, let’s be honest, any age at all).
Why Is Math Homework So Tricky These Days?
Mark’s story is just the latest in a long line of parents and grandparents scratching their heads over elementary school math. And it’s not just about fenceposts and fractions.
The way math is taught has changed dramatically over the years, with a greater emphasis on understanding concepts rather than just memorizing formulas.
That’s a good thing in the long run, but it can make helping with homework a real challenge for those who learned math “the old-fashioned way.”
Also read: The math problem for kids that’s baffling grown-ups—Can you crack the code?
A 2013 study in The Journal of Experimental Education found that students in high-performing schools were spending more than three hours a night on homework, leading to increased stress and even health problems.
While homework can reinforce learning and build good study habits, it can also create confusion and frustration—especially when the instructions aren’t crystal clear.
But let’s not forget the humor. One commenter shared a story about a cleaner working from 8 to 12 o’clock, thinking it was four hours for four floors—only to realize it was actually five floors.
Another pointed out that dividing a sandwich for a math problem had stumped a 6-year-old girl (and, presumably, her parents too).
Read next: Think you're smarter than a 5-year-old? This kindergarten homework puzzle has stumped PhDs!
Have you ever been stumped by a child’s homework? Do you have a favorite “trick question” that caught you off guard? Or maybe you’ve got a tip for making sense of today’s math assignments? We’d love to hear your stories, your struggles, and your solutions!
