八枚一元硬币的启示

八枚1元新币有多重？小六数学考卷问题引争议，有人认为这不是一般的数学考题，但受访数学补习老师认为，这类题目在教学范围内。

上周五的小六会考数学试卷中，有一题要学生估计八枚1元新币的重量是多少，6克、60克或600克？一名李姓网友在当天下午5时50分就立刻上教育部的面簿投诉，她认为，题目里的硬币有可能是金币、塑料币甚至是纸币。

受访的补习老师表示，这种题目并不罕见。有25年补习老师经验的Ann Tutor补习老师陈金思（43岁）说：“这个题目符合小学的数学教材。学生们在低年级时就已经学习如何估算，例如估算一个西瓜的重量。”她指出，这种问题已经被问过很多次，有些老师甚至会带学生去超级市场，实际动手学习。

http://www.tnp.sg/news/singapore-news/dont-know-weight-1-coins-dont-worry-about-it

By AZIM AZMAN

The Primary School Leaving Examination (PSLE).

For parents, the ongoing examination might cause loss of sleep and/or hair, or weight gain or a combination of all three things. 

The exams determine a child's educational path after six years primary school education, so it's understandable that the PSLE period is a stressful time for both parents and pupils.

Every year, both students and parents worry about tough or confusing questions, and this year was no different. 

One question in the Mathematics paper which students sat for last Friday (Oct 2) caused a bit of a stir.

What is the likely weight of 8 $1 coins?
(A) 6g
(B) 60g
(C) 600g
(D) 6kg

One Facebook user even went as far as to complain on the Ministry of Education's Facebook page, calling the question "misleading" and asking if it was a Mathematics exams or a logic test.

Is the anxiety warranted?

Perhaps not - here are some reasons why.

The question is worth only one or two marks

According to information from the Singapore Examinations and Assessment Board (SEAB), the multiple choice questions are worth either one or two marks.

That's a small percentage of the total marks in the whole paper.

So while not knowing how to answer one question might be distressing, it is not the end of the world.

It is a valid test of the pupil's estimation abilities

You might be tempted to dismiss the question as being irrelevant to the syllabus because what are the chances that anyone would know the weight of a $1 coin?

However, a check of SEAB's syllabus show that one of the objectives for the primary school curriculum is for the pupils to be able to "develop ability to perform estimation."

Clearly the question is asking pupils to show their ability to estimate.

It is a test of the pupil's logical abilities

By sheer elimination, the pupils should be able to arrive at the answer.

Option A, 6g, is too light while option D, 6kg, is simply too heavy.

That leaves option B and C.

It cannot be option C because it would mean that eight coins weigh slightly more than half a kilogram.

That's about the same weight as 600ml of water. 

Have you ever felt like you carried 600ml of water in your wallet?

It is a good lesson on the importance of common sense

Even if you got the question wrong, take it as a lesson about the importance of common sense.

There will be numerous occasions in life where you don't have all the information to make an informed decision.

So you will just have to make a choice based on your most logical guess.

There are still two more days of examinations to go in the PSLE - it ends on Oct 7 for those taking Higher Mother Tongue - so don't fret over one question.

There are plenty more waiting.

Good luck!