After I had practised the SMO Junior questions and after my teacher asked us to complete the P5 thinkingMath@onSponge Conquer Problem Sums, I realised that something was wrong ...
Page 149.
Based on Pythagoras' theorem, AB is 8sqrt(10). But without knowing Pythagoras' theorem, a student will calculate AB = (28 x 18)/12 = 42???Page 148.
Based on Pythagoras' theorem again, how can the three lengths of a triangle be 15, 20 and 30???Page 146.
If the lengths of the triangle are 8, 10 and 14, the area should be sqrt(s(s-8)(s-10)(s-14)) where s = (8+10+14)/2. Hence, area = 16sqrt(6). But then, how can the height be 7 if the base is 14???Page 145.
How can the hypotenuse be 8, which is shorter than the base length of 20???There are more mistakes in the book, which I am too lazy to scan and highlight in this post.
Some books are a joke. They contain numerous mistakes and in fact, some of these questions are copied from other books where the numbers were changed and became wrong!
ReplyDeleteHaha, that is very common.
ReplyDeleteAll those qns don't need Pythagoras theorem...
ReplyDeleteWithout knowing Pythagoras theorem,the student will do this:
(28x18)/2=42
(I check ans sheet already. Its correct)
page 145:
ReplyDeleteEasiest!
Base: 5cm
Height:20cm
Area= 1/2 x 5 x 20 = 50
pg 148:
ReplyDelete(20 x 15)/30 = 10
pg 146:
Because of right angle...
Base: 14cm
Height: 7cm
I hope you can prove that their questions were copied. Otherwise you are slandering that company and/or the publishers.
ReplyDeleteYes, I agree with anonymous
ReplyDeletethe problems are overdefined.
ReplyDeletevery careless writers.
I guess Yong Chen doesn't understand that.
For example, the values given in the right angle question are not consistent with each other.
just because you can "work it out" doesn't mean it's right, Yong Chen.
are you suggesting everything taught in primary school is correct? many times resources are incorrect but done that way on purpose to teach something. only when those students get older do they learn what they learned in the past may not be exactly as taught. i think your post is a little naive. as a tutor i teach both primary and secondary and use that chapter for teaching my primary kids because they are able to show different things from one picture. i would never recommend it for my secondary students learning pythagoras theorem. i think the error is on your teacher's side for suggesting something he clearly has not done before. also i think you need to be careful with your post. i agree above you are slandering - what proof do you have they copied?
ReplyDeleteI realise that my comments are much later than yours. I am a teacher at a well know primary school who uses these books extensive due to the structure, organisation and approaches to solving. While we don't necessarily agree with all what's there I do find this particular chapter rather useful because we can clearly use the visuals with the different values along the sides. To be true to our friend Pythagoras, would mean many triangles instead of one to achieve the same result. Perhaps the authors / publishers could have made a footnote to say this is for presentation purposes only. As a secondary student surely you have come across text books before where the proportions are clearly wrong, the sentence structure is clearly wrong or the questions are far too vague. I say give them a break - this is the best assessment book introduced for a long time and will continue to use it. Personally, your professor should be scolded for not knowing what assignment he was giving out.
ReplyDeleteI suggest you remove this entire blog before the authors find out and come after you for slander !
Hi Anonymous on 19 September,
ReplyDeleteThe post was written by Lim Li, a P6 student at the time of posting. Don't quite get you when you mentioned 'your professor'. What she wrote about the mistakes were pure facts, nothing slandering about it. Whether the assessment book is good or not is subjective. The fact remains that there are mistakes in the book!