9.82+9.81+9.80+9.79+9.78; thus largest is 9.82?

Q11. 9:1. So there are 10 parts. 180cm squared, divided by 10 = 18cm squared = 1 part. So 18 cm squared, for the shaded area.

Qu 12. 60% used means 40% of paint remaining. 40% = 5 days, therefore 8% per day used. (equal amount of paint used each day) Plus 7 days x 8% = 56%. Which leaves 4% of paint, which = 2 litres. So, every 2 litres = 4%. How many 4% = 100%? 25. 25 x 2ltrs = 50 litres.

Pattern 2 = 1+3 or 1 + (1x3) Pattern 3 = 1+3+3 or 1 + (2×3) Pattern 4 = 1+3+3+3 or 1 + (3×3) Therefore, Pattern 13 = ....? Try it!

Actually I can do the first part as 3 x 13= 38 But the answer is 37 How to explain this?

No leh, its not 3x13, if u look at the pattern carefully

My pattern 4 is not 4x3

Anyway it is: Pattern 13 = 1 + (12x3)

Pattern 88 will be 1 + (87×3)

You method is more easy to understand

Also can, there are more than 1 way to look at the pattern.

But I just dnt understand why -2

Make use of the diagram to explain to yr child how the pattern is derived. My "1" came from the centre piece of sweet, which is there in every pattern.

Thanks will teach her your method

Because they take that 1 piece as a set of 3. Which is not correct, so they have to subtract 2 away.

Looks so simple yet so difficult to explain

I wish i could verbally explain! So not used to explain through typing...

That method is easy because the pattern number coincides with the number of sets of 3. They have to minus 2, because the center piece is not a set of 3 but it is 1 piece on its own. Hence, have to minus 2.

That method as in the school's method.

U mean yours or mine?

Yours

I was trying to explain that each method is easy in their own ways

Thanks so much... I'm really bad in maths

I get exposed to Math sums everyday in school.. u dont. So not fair to say u are poor in Math. Practice makes perfect

Are u a teacher?

Yes always tell my girls tat too, practice makes perfect.

Yesh, especially for Math! :)

I alway love maths teachers! Are u staying at the east?

North east!

Hola Cyn. Please bear with me and allow me to explain how a general formula based on the working that you had posted in this thread can be derived. As per convention, we assign n as the variable for pattern number. So for Pattern 1, n =1. For Pattern 13, n = 13. Since every pattern after Pattern 1 increases by 3 candies over the previous pattern, 3n is an element of the general formula. However, we need to compensate for Pattern 1, which contains only a single candy. Hence for n = 1, 3n = 3. Two candies need to be removed to fit Pattern 1. That is why the working you posted shows the subtraction of 2 from 3 x 13 for Pattern 13. The general formula for the number of candies in any particular pattern is hence 3n - 2. I hope this helps you understand.

The ability to derive the general formula for patterns will come in handy at the upper primary, secondary and tertiary levels. It pays to know how to do it quickly and effortlessly. Regards

Wohooo thanks Xavier Sng for your late night coaching. Really love this group.

Cyn Puan, try this to see if it helps: Step 1: Ask your child to add 2 to each number, 1, 4, 7, 10, ... become 3, 6, 9, 12,... (I hope your child knows the 3 - multiplication table well.) Step 2: Figure 13 will be 3 x 13 = 39 Step 3: Now, subtract the 2 which we added initially. Tada... answer is 39 - 2 = 37 Hope this helps.

Happy to help, Regards

Hi hi Raymond Ng thanks so much My gal asked me why must add 2. Does it mean this type of question standard format by adding 2? Or will be adding 3 or more? Sorry for the stupid question..... I'm really poor in Maths especially models. Sometimes I can do but can't explain. Xavier Sng 😊

Such type of sequences is known as Arithmetic Progression (等差数列) whereby the difference between consecutive terms is fixed. The trick is to make the 1st term match this difference in the first step. There're tricks to writing down the general term by mere observation, but I only teach such tricks to P5 & above ☺

Noted with thanks Raymond Ng. I will try out another similar questions. If u come across any similar questions can u post on my wall so tat I can try to do it. Thanks so much

No need so mafan lah... I give you a few now... 1 enough?

Cool, thank you Cher.... I gg to try now

A good question, Mister Ng.

Another variation, by observation.

Cyn Puan, that is like the simplest of the simplest ie tip of the iceberg. Pattern questions can be 1st order (difference is fixed), 2nd order (difference of the difference is fixed) or 3rd order (you get the idea) or miscellaneous. At Pri school, 2nd order is already a nightmare for most. But there're tricks to get the general term within seconds (beyond that, too slow, remembering time isn't on your side in exams) Since your child is only P3, knowing the above series will suffice, for the time being ☺ Before I end, try this tricky but not difficult one: 😉 Write down the next two terms for the following sequence 1, 1/2, 3/7, 2/5, 5/13, __ , ___

Another good question.

Xavier Sng, since you crave for good questions, here's another one to quench your thirst ☺ Row 1 1 Row 2 2 3 4 Row 3 5 6 7 8 9 Row 4 10 11 12 13 14 15 16 ... In which row does 1999 appear?

Thanks for the question! Row 45.

Your students are very fortunate to have a good coach in you. Kudos.

Many thanks to Mister Raymond Ng for his challenging but interesting questions. There are a few ways to solve the last question, but more advanced methods and formulas are required to make them profitable to use on the question. As Mister Ng had mentioned, the questions that are presented here are mere tip of the iceberg. Parents need not be too concerned, however. Firstly, questions on sequences are not significant in numbers in examinations at the primary level. Secondly, such questions that appear do not have the same difficulty level (unless your children are in the Maths Olympia class, which means you are asking for it, or that your children's school's HOD is the first cousin of Hannibal Lecter). Like what Yueh Mei had wisely advised us, these questions are good as challenges, but don't lose sleep over them. Regards.

Xavier Sng are you a Math tutor?

Yes, most unfortunately for the kids that I coach, I am one. As for patterns 30 or 100, the respective answers are 88 and 298. Use the formula 3n -2 which is explained in this thread and you do not need to do a listing.

As for whether such questions are at P3 level, I tend to take a detached view of it. A lot of children can understand the concept once they have been exposed to it, and the children can be as young as in P1. If a child cannot see the way sequences work, it does not mean the child is stupid. The child may just be more receptive to other areas in mathematics, or that the child has a mental aversion towards such topics.

Thanks. I know the method but i was just wondering if my daughter will be tested on such question because she is in P3 currently.

Expose her to it as an extra curriculum activity then. No harm doing it if you and your daughter can treat it as a fun thing to learn even if this is not in the scope of tested topics.

I don't think your students are unfortunate since you can come out with different methods to coach them. I like your chop-chop -curry-pok way😂

Well, not every student can accept or handle different methods, but it is a good practice to see what they can comfortably, or should I say least uncomfortably deal with. If the students learn how to approach problem-solving efficiently, the methods are just mere tools. They can even derive their own methods, which they have never failed to amaze me till this day.

Agree. Like what Socrates said " I cannot teach you anything, i can only make you think ".

A further extension to that maxim is that we must always seek to challenge the conventional wisdom. Established methods may have worked for ages but that does not mean that one cannot seek to improve upon the way things are done. It is exactly because many of our educators seek more efficient manners of solving problem sums that we can derive different pathways to the solutions.

Mister Raymond Ng, I hope, will understand and agree with my views as I see that he utilizes many efficient and speedy "chop-chop-curry-pok" methods. All credit to him.

Not only my child learned, I learned a lot too. Thanks

We all do, which is why there is such a forum.

Xavier Sng do u have anything to recommend? I do collect some of the questions here to let her try out , including this question posted by Cyn which she is able to solve.

I pretty much use only past year papers from the various schools as I think that they are the most relevant / appropriate tools to coach the students. I hardly ever use assessment books.

Thank u

For such sequence questions, they do appear in lower secondary exam papers as well. Modify those questions (or just serve them plain) and see if your child can handle them?

The disadvantage of using past year papers is that they are not topical. Someone has to ferret the questions out for the students to attempt. However, I understand that there are folks who have done that and group the questions into topical format. Hunt for them at Popular bookstore.

Wah! Such lively discussions here! Those questions brought me back to my EMaths days in my Secondary school!

Is the answer for (a) 5 weeks?

No, it is 5

6

$1.20= n Week 1- n Week 2- 2n Week 3- 3n Week 4- 4n Week 5- 5n Total-- 5weeks,= 15n 15x$1.20= $18 He saved $18 after 5weeks(answer)

a ans is 6

(b) $18 minus $17.25= $0.75(ans)

6 weeks his saving will be $25.20...that is wrong

Week 1--$1.20 Week 2-$2.40 Week 3-$3.60 Week 4-$4.80 Week 5-$6.00 ------------------------ 5weeks-$18 (more than $17.25) -------------------------

Week 1--$0 Week 2-$1.20 Week 3-$2.40 Week 4-$3.60 Week 5-$4.80 Week 6 -$6.00 ------------------------ $18 can buy $17.25. So left $0.75. An I right? -------------------------

That is 5 weeks of saving LOL.. end of first week is zero...zero is not a saving...

I agree with Izam that $1.20 is the first week's savings.