Is it just me or the Perms & Combs in Cambridge textbook so hard? (1 Viewer)

[potpal]

So I have been doing the perms and combs exercises in the 3u textbook. Most of them are fine but there are some really mind-twisting questions that I can't seem to fully understand no matter how many solutions I read And these questions are in the Development section, not even Enrichment. However when I do prelim past papers I have no problem doing the perms &combs questions at all. Why is it like this?

 

[jimmysmith560]

As far as I am aware, the difficulty of the Cambridge textbook questions (including those that you may be struggling with) exceeds that of most other textbooks and is the reason that many students (especially those aiming for high marks) ensure that they use this textbook for their preparations. If you think that you may need to review the basics of permutations and combinations, then you may wish to use Maths in Focus, as it is considered a good textbook when the aim is to familiarise yourself with a particular concept. However, you do not seem to be in need of this, especially since you are not struggling with the rest of the questions and are able to complete the relevant questions within past exam papers (especially if you are attempting the more challenging papers).

It is normal to face difficulties with particular questions. When this happens, you should preferably discuss the specific questions that you do not fully understand with your teacher and seek further explanation/clarification. You can also post questions that you struggle with on BoS (this applies to all topics, not just permutations and combinations), with your working/approach (if applicable) and other people may be able to indicate where an error was made and how you could avoid such errors going forward.

Additionally, my understanding is that some of the questions in the Cambridge textbook are not intended to be reflective of exam question difficulty and/or format. Instead, they are solely designed to challenge students. In any case, while completing textbook questions can support your preparations, completing past papers should be a priority since you become increasingly exposed/familiar with exam-type questions, allowing you to form relevant patterns that can assist you when sitting your exams.

I hope this helps!

 

[carrotsss]

If you’re doing fine with exam questions then I wouldn’t worry about it

 

[potpal]

Thanks so much for your replies! I'll worry less about it now haha

 

[ZakaryJayNicholls]

So I have been doing the perms and combs exercises in the 3u textbook. Most of them are fine but there are some really mind-twisting questions that I can't seem to fully understand no matter how many solutions I read And these questions are in the Development section, not even Enrichment. However when I do prelim past papers I have no problem doing the perms &combs questions at all. Why is it like this?

I've been using the Cambridge books for the past 4 years and I can assure you that the Cambridge books are definitely not the hardest, but they are really excellent.

Hard tier books: Terry Lee [Advanced Mathematics/etc], Bob Aus & Bernie Fitzpatrick [New Senior - Fun Fact: Bob Aus was the head math teacher of math when I was in year 7/8 at Merewether High], the rest of the hard tier books double as uni texts [eg stewarts/anton/spivak/strange].
Middle tier books: Pender et Al [Cambridge], Howard [Howard HSC math].
Low tier books: Grove [Focus], excel, oxford, there are quite a few low tier books.

The Cambridge book is really good, but definitely not the hardest.

If you plan on going into a field concerning combinatorics [theoretical computing, cryptography, number theory, quantitative chemistry] then the types of questions you will be exposed to in these fields are absolutely mind boggling compared to anything you will have ever experienced. So, what the books try to do is ratchet the difficulty up a little by making the examples in the latter part of each section more challenging, to expose people to slightly harder applications of the concepts, so as to make sure people have at least seen some of the kinds of things they may be doing later. The harder questions for fact/comb/perm/binomial can get rather wild, so don't worry too much if you are struggling with the harder examples.

 

[potpal]

I've been using the Cambridge books for the past 4 years and I can assure you that the Cambridge books are definitely not the hardest, but they are really excellent.

Hard tier books: Terry Lee [Advanced Mathematics/etc], Bob Aus & Bernie Fitzpatrick [New Senior - Fun Fact: Bob Aus was the head math teacher of math when I was in year 7/8 at Merewether High], the rest of the hard tier books double as uni texts [eg stewarts/anton/spivak/strange].
Middle tier books: Pender et Al [Cambridge], Howard [Howard HSC math].
Low tier books: Grove [Focus], excel, oxford, there are quite a few low tier books.

The Cambridge book is really good, but definitely not the hardest.

If you plan on going into a field concerning combinatorics [theoretical computing, cryptography, number theory, quantitative chemistry] then the types of questions you will be exposed to in these fields are absolutely mind boggling compared to anything you will have ever experienced. So, what the books try to do is ratchet the difficulty up a little by making the examples in the latter part of each section more challenging, to expose people to slightly harder applications of the concepts, so as to make sure people have at least seen some of the kinds of things they may be doing later. The harder questions for fact/comb/perm/binomial can get rather wild, so don't worry too much if you are struggling with the harder examples.

Thanks so much for the detailed reply! I really appreciate it

 

[synthesisFR]

Yooooooooo nice

 

[ZakaryJayNicholls]

That's really interesting. I recently graduated from there, do you have any other fun facts from your time there?

The only other interesting fact I remember about Merewether is that during the 2005-2010 period (A period in which we had 3 separate principles - the time when I was there - this was also directly around the GFC) we had two older male teachers terminated/leave for either being charged with historic child sex offenses and possession of child pornography.

It is also well known that the cool students hang out in the quad.