The problem 'Lan's house is 200km from school': Funny or unrealistic?

Netizens were once excitedly discussing a math problem with the following question: "Lan's house is 200km from school, it takes Lan 10 hours to cycle from home to school, what is Lan's cycling speed?".

For this problem, we will apply the velocity formula: "S = vt".

From there, we get the answer: "v = S : t = 200 : 10 = 20 km/h". Thus, Lan's cycling speed is 20km/h.

What people should pay attention to here is the data that the problem gives. Who would go to school 200km away from home, and also ride a bike all day? Just going to school alone takes 10 hours, so where does Lan find the time to study now?

Although it is just a simple problem about calculating speed, the unrealistic question made the online community laugh out loud, and left many humorous comments as follows:

"Lan is really determined. Every day she cycles 400km round trip to school."

"I feel sorry for Lan when she rides her bike to school. Why don't you transfer to a school closer to home?"

"Who will teach Lan after cycling for 10 hours to get to school? She has to finish two sessions before she comes to school?"

Mathematics is an extremely interesting subject and requires a lot of brainpower. Not only dry numbers, Mathematics also contains countless logical thinking questions, requiring students to have a high IQ, plus the ability to observe and closely associate to be able to solve. Because many times Math puzzles give "trap" data and we have to think carefully to come up with the right answer.

1. Problem 11 - 4 = 7

A teacher named Truong in China has made a parent extremely angry. Specifically, this mother believes that the teacher has carelessly graded and crossed out the correct answer in her child's math test. Accordingly, the test has a question as follows: "There are 11 light bulbs turned on in the classroom. After 4 light bulbs are turned off, how many light bulbs are left in the classroom?"

Like many other students, this parent's son gave the answer "11 - 4 = 7". However, the teacher crossed out the answer and marked it "wrong". When reviewing her son's test, the mother was angry and immediately went to school to meet and question the teacher. However, the answer she received made this parent extremely embarrassed. Because she realized that not only her son but also herself did not have the ability to think logically and look at problems carefully.

Ms. Truong said that this is a question that tests children's intelligence and thinking. The answer to the problem is 11, not 7. Because after turning off 4 light bulbs, or even turning off all the lights, the total number of lights in the classroom does not change, it is still 11. Many students did not think carefully about the question and hastily gave the answer. In fact, the problem asked about the number of light bulbs left in the classroom, not the number of light bulbs that were still lit.

The other parent, after hearing the teacher’s explanation, admitted his mistake for reacting too hastily. In fact, there have been many elementary school math problems that have caused parents to argue with teachers because they thought their child had been graded incorrectly. These problems look simple at first glance, but to give the correct answer, students must pay attention to each semicolon.

2. Problem "1.2 6.8 = 8"

A young father shared his daughter's elementary school math problem on social media and received attention from parents. The problem asked the calculation: "1.2 6.8 = ?" and his daughter answered 8. However, the teacher immediately crossed out this answer and deducted 3 points for the mistake. Too surprised by the teacher's decision, the young father texted to question the reason.

The teacher then explained as follows: "8 and 8.0 are the same value but there is still a difference. In terms of calculation rules, there are no special requirements and instructions but the decimal point needs to be retained and cannot be simplified." This explanation later received agreement from the parents.

Calling the doctor "sister - brother", the patient's face was straightened, netizens argued Đình Như20:04:50 22/02/2025Communication is the core issue in human life, right from the primitive society. Along with the development of modern society, the issue of communication becomes more and more important.