Are you smarter than a 12-year-old? #2 \ stacker news ~science

909 sats \ 16 comments \ @cryotosensei 3 Nov science

zaps forwarded to @south_korea_ln (21%)

Well, just thought I would start an occasional series on notoriously challenging Maths problems that appeared in Singapore’s Primary School Leaving Examination. It’s a dog-eat-dog world in our educational system. Some questions are so tough that children come out of the exam room, whimpering. Their parents subsequently cry foul, attracting intense media scrutiny for a week or so. Hard to imagine how such questions corral the attention of the entire nation, huh.

Anyway, some of these problems plagued me during my childhood. High time for me to learn how to solve them so that I can train my son to beat the system. Will like to thank @south_korea_ln for demolishing my inertia with his Daily Maths puzzle; otherwise I doubt that I would have the discipline to research these questions.

This question appeared in the 2023 Maths paper.

Figure 1 shows a trapezium which has a perimeter of 96 cm. Jiayu joins three such trapeziums to form Figure 2 which has a perimeter of 204 cm.

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45 sats \ 1 reply \ @JesseJames 3 Nov

In the US the passing grade for this exam would be (unfortunately) 0.0000001%

0 sats \ 0 replies \ @cryotosensei OP 3 Nov

Well the US has always been a literary giant. Though you guys clinch many Nobel Prizes, so it’s not like talents are scarce

24 sats \ 2 replies \ @Roll 3 Nov

I do not get this title...... "Are you smarter than a 12-year-old?"

-What is the definition of smarter? -Why the need to compare to someone else? moreover to a child 12years old? -We are all diferent (culture, age, sex, race, nationality, religion....) with our unique way but in ONE so WHY!!!

7 sats \ 1 reply \ @cryotosensei OP 3 Nov

It’s a tongue-in-cheek reference to the popular tv show, “are you smarter than a fifth grader?” Or you can take it as a click bait title haha.

Smart here means book smarts. Sixth graders who can solve questions like this are likely to get more than 90 for their Maths exam. So they are smarter than me, for I definitely won’t be able to get 90 haha. If I undergo hothousing, I may acquire the techniques to solve all these pesky problems though. But which adult has the time and patience these days?

Well, these academic results have real-world implications in my country. Students with high scores get funneled to the elite junior high schools. We are the world kinda mentality doesn’t work when afraid-to-lose Singaporeans are fighting for limited places in coveted schools

0 sats \ 0 replies \ @Roll 3 Nov

In all around the world, the word "smart" is a "key" word which lead to competitive attitude, discrimination, arrongance...and so on.

A smart person is : -The one who is able to solve mathematic or whatever problem or -The one who is able to manage his emotions, energy, mind and body..

That is what i was trying to refer ;)

24 sats \ 1 reply \ @Coinsreporter 3 Nov

I thought we are both English teachers and we don't know absolutely nothing about Maths.

Bur it's good I must learn a bit of maths myself for I'm also a father now.

0 sats \ 0 replies \ @cryotosensei OP 3 Nov

Actually I was supposed to be a Maths and Chemistry teacher. But I switched my major to Linguistics in college, hence I’m now an English and ex-Science teacher. Thank goodness. My Maths isn’t as powerful as my English haha

0 sats \ 8 replies \ @south_korea_ln fwd 3 Nov

I must have made a mistake, because the only way for it to work out is to have a negative length for RS ;)

I'll check again later when i have pen and paper in front of me.

10 sats \ 7 replies \ @south_korea_ln fwd 3 Nov

Oh, my bad. I forgot the overlap between the two top trapezia in Figure 2. My answer in (a) was 42 (@Aardvark~~), instead of 21.

Answers: (a) 21 cm (b) 13 cm

0 sats \ 6 replies \ @Aardvark 3 Nov

Odd, I must be making the exact same mistake.. I've done it several times now and I also keep coming up with 42..... Are you sure it was a mistake?

24 sats \ 5 replies \ @south_korea_ln fwd 3 Nov

Yes, 21 cm is the correct length.

3 times the perimeter of a single trapezoid is 288 cm.

288-204 = 84cm. 84 cm corresponds to 4 times the length of PQ. Twice for the overlap between the top 2 trapezoids in Fig. 2 and twice for the overlap between the top left and the trapezoid just below in the same figure.

84/4=21 cm.

66 sats \ 3 replies \ @Aardvark 3 Nov

Oh, I see where you made the mistake. You did actual math instead of just guessing 42....

Don't worry, it happens to the best of us.

40 sats \ 1 reply \ @south_korea_ln fwd 3 Nov

You got me ;)

0 sats \ 0 replies \ @Aardvark 3 Nov

0 sats \ 0 replies \ @cryotosensei OP 3 Nov

No worries, I will tag you when I have a question that requires 42 as the answer

0 sats \ 0 replies \ @cryotosensei OP 3 Nov

Splendid!

Sensei approves