Prepare to Be Stumped By This Math Problem Meant for Fifth Graders

iStock
iStock

Math is hard. Just ask Mumsnet user PeerieBreeks, who posted a ‘simple’ math riddle meant for fifth graders to the parenting website, and ended up with more than 500 comments—many of them from adults struggling to come up with the correct answer. Here’s the riddle:


For the most part, the problem-solvers who shared their answers all believed that the man made a profit, but whether it was $10, $20, or $30 seemed to be in hot dispute. Can you figure it out? (Scroll down for the answer. We’ll give you a minute …)

 

 

 

 

 

The wording of the riddle, not the math, seems to be what’s throwing most people off. Because the transactions in question relate to the same horse, people are looking at it as a single, four-part transaction—buys, sells, buys, sells. But the correct way to look at the problem, and figure out the answer, is to look at it as just two transactions: a man bought a horse and sold a horse. A man bought a horse and sold a horse. (The man could just as easily have bought and sold a dog in one of those transactions and it wouldn’t change the outcome.)

All of which is to say that the correct answer is: The man made a $20 profit.

Can You Find the Lost Items in This Santa's Workshop Puzzle?

iStock.com/LiliGraphie
iStock.com/LiliGraphie

If the holiday season has you feeling stressed, here's an opportunity to take a break from making travel plans and brainstorming gift lists. This picture puzzle from Attic Self Storage features six hidden items, and it takes most people a few minutes to find them all.

The scene below depicts the chaos of Santa's workshop leading up to Christmas Eve. Hidden among the elves and toys are some lost items: a stocking, a nutcracker, Santa's hat, a mince pie, a Christmas cracker, and a robin. If you aren't sure what you're looking for, a visual key of the items is included at the bottom of the image.

Santa's workshop brain teaser puzzle.
Attic Self Storage

It took Attic Self Storage staff members 3 minutes and 26 seconds on average to solve the brain teaser, so that's the time to beat. After completing the challenge, see if you can spot the sheep hidden among the Santas in this holiday-themed puzzle.

You Can Gift Your Favorite Nerd a Subscription to Famous Letters From History

Letterjoy
Letterjoy

Letter writing may be a lost art at this point, but you can still give someone the gift of getting a great letter in the mail, without ever picking up a pen yourself. Letterjoy, a subscription service for historical letters, sends out a different archival letter each week, giving subscribers the opportunity to dig through their mail and find a work of great writing rather than a pile of junk advertisements.

As part of the service, Letterjoy sends out one authenticated historical letter or telegraph each week, according to monthly themes. The letters are largely drawn from the last 400-plus years of American history, sourced by Letterjoy founder Michael Sitver from historical archives and private collections. Previous monthly themes have included "presidents and the press," "the right to vote," "Civil War spies," and "the birth of aviation." The letters often come from famous figures like Abraham Lincoln, Albert Einstein, Winston Churchill, Clara Barton, and the Wright brothers.

Recipients don't just get a photocopy of an archival letter. Each letter is custom-designed by Letterjoy, either typed up on a Smith-Corona typewriter (for more modern missives) or handwritten by designers and enhanced with software. The goal is to make each letter look and feel as authentic as possible while maintaining readability—since the whole point is to read the letters, not just look at them.

Every letter comes with a context section that explains what the letter is and why it matters, including who the letter-writer and recipient were and the historical events surrounding its writing.

You can buy someone (or yourself) a yearly plan for $160 ($13.33 a month), a six-month plan for $100 ($16.66 a month), or a three-month plan for $50 (also $16.66 a month). Discounts are available for educators who want to use the letters in their classrooms.

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