A seemingly simple math problem for fourth graders has gone viral on Reddit after several adult users admitted they had trouble understanding the statement. Online discussions highlight the ambiguity and wording of the exercise, but also the differences between educational systems.
A 4th grade math problem stumped adults PHOTO: Shutterstock
The post contains the photo of a problem from a math culture magazine for students: “On a board, Adina wrote 3 + 4 + 5 + 6 + … + 89. Tudor chooses two numbers at random, erases them and writes a number equal to the sum of the two numbers reduced by 2. Adina chooses two other numbers, erases them and writes their sum reduced by 2. Which number will be written last on the board?”
The post was accompanied by the author’s comment, which admitted that the exercise had overtaken him: “As an adult who did school I’m sick of, I have real trouble understanding even the statement of the problem. And they expect a 4th grader to solve it. Meanwhile, school in the West is much more relaxed and done at the level of the students, that’s why we are the core of the planet and Westerners are woe to them.”
Harsh criticism of the statement
In the comments section, the discussions quickly turned ironic and sour. Several users have complained that the issue is “badly written” and that it does not provide enough information for a clear resolution.
A user asks: “The problem is that they can’t write the problem statement. Which last number? Do the two keep deleting two numbers and writing their sum down by 2 until they get to a single number? You have to calculate that sum with the two changes made by Adina and Tudor? What is Tudor looking for in this equation?”
Another comment pointed out the ambiguity of the choice of numbers: “Where are the two numbers chosen from? From that series or random off the top of my head? Where are the numbers deleted from? From the series? Wtf, what’s with that statement?”
The confusion is also shared by other users: “I don’t understand the wording of the problem… what do you mean what number will be written last on the board?”
Another commentator criticizes the exercises presented as “Olympic”, but vaguely worded: “The wonderful incomplete statements and presented as «of the Olympics»which only the teacher’s trained students can solve after dozens of identical exercises”.
A possible solution, only if you assume certain things
Among the commenters, one user tries a mathematical approach, but points out that the issue remains ambiguous: “As far as I can tell, it’s a game where the two take turns replacing two random numbers with their sum minus 2, and the game ends when only one number remains. Basically, you have to calculate the initial amount and subtract from it 2 * the number of steps. You have 87 numbers, you will do 86 steps until there is only one number left. The initial sum en(n+1)/2 – 3, so 4002. Subtract 86*2 and you get 3830. The statement is a bit ambiguous, but this is probably the solution, beyond the formulation the problem is easy”
Others completely reject the idea that there is a single answer: “There is no answer to it… If we go strictly by the statement, there is not a single number. If Tudor takes the numbers 3 and 4, he will write 5. If Adina takes the numbers 5 and 89, he will write 92. So the answer is in Adina’s hands“.
Another user quips: “School prepares you for real life, right? This statement of f***t prepares the child to interact with poorly written, ambiguous and stupid laws. Big brain moment”.
The discussion also reached the teachers
Some comments criticize the way teachers frame and explain problems: “That’s the problem with our profiles. I don’t know how to explain. They don’t know how to convey information.”
Others point out that the problem comes from an optional magazine for students with a passion for math: “It’s a problem from a math magazine, so it’s optional. Some in the 4th do all the hard things, for parents at least”.
