The child must know that the total between both Simon and Rex stays the same throughout. So for the ending, Simon 7u, Rex 1u. Total is 8u. Since they have equal start, use the 8u / 2 = 4u. Hence, 7u - 4u = 3u. :)

Thanks.

Work backwards is one way. Start with the end and slowly work to initial situation where the number is equal. The main thing is that you see the significance of the 8 stickers.

If you need more help then this diagram may help.

I again recommend the user friendly Trial n Error method, answer is Francis had 32 at first.

Dr Yeap Ban Har is here? Oh wow!

Gonna ride on this to ask Dr Ban Har Yeap this question posted earlier in this page. Hoping for a non-algebra solution to the question.

Ban Har Yeap. How do you get the 3 unit for Emma?

First they have same units as 1:1 then Emma bought twice, so emma will have 2 + 1 = 3 units

Janis Chong when I first read it I also thought it was saying she had twice as much, but she actually BOUGHT twice as much and therefore she had the original amount and twice as much along with it.

Thanks,more helps pls. Can I assume 1 unit = 8 stickers as that is the only available numbers. Trying to learn on how to apply equal concept.

The penultimate step would be to continue Dr Ban Har Yeap bottom part of his model and work out what one unit (yellow bar) is equal to. What year is this for?

Janis Chong, Ban Har Yeap's diagram shows that each long blue bar = one yellow+8. If you replace all 3 long blue bars with the yellow+8, you will get __yellow+__. Then by letting 1 yellow bar be 1 unit, see if you can deduce what 1 unit equals to.

Sorry really cueless on how to solve that ... Have another similar question need to solve ..

Mohi Uddin Ahmed This is P3 work.

Trial n error method expln is like simple n ordinary normal person like you n me which u really write you what u think in your mind, u draw column to fit in the description of what u r told or provided with the info in the question itself, if doesnt agree just continue with the most 3 or 4 tries the most, u can see light in the tunnel, it is soòoòoo user friendly that just ordinary housewife with plain normal.maths literacy SHOULD be able to arrive at the correct spo or answer, cheers i assure you NO NEED to crack sooooo hard, believe n trust me

Here you go, Janis Chong...

Really appreaciate that.Let me digest the solution. Thanks.

Janis Chong Everyone has explained it. You can also use this to see why 1 unit equals 8 stickers. Of course guess-and-check works as well. This is a challenging problem for P3 - typical word problems for P3 is not usually of this level of difficulty.

Thanks everyone for the inputs..it has been really helpful

Don't mention, u r most welcome by everyone and all trying to help, cheers n relax

This is really challenging for Y3 and I doubt many would be able to handle it in England. I think I would struggle to teach this to them too.

Primary 3 is Year 4 age.

Even year 4, most would struggle, but year 5 I think this wouldn't be a big problem, but I suppose it's all about having this approach already instilled from year 2 or Primary 1 for Singapore

I did it this way

using my Distinguished Units Method not Algebra not Bar Diagramming (don't worry about drawing wrongly) the trick is to use different shapes to envelop different units. Then use LCM, and then change everything to a common ratio unit. The "problem" just crumbles immediately !!!

Nadirah using my Distinguished Units Method Since we have 1 unit for the "circle", it is easy to multiply it. We multiply it by 5 so as to equate with the 5 "circle" units. now it is easy to compare the 25 "square" units with the 4 "square" units. We realise that 21 "square" units is 588. From here onwards, the problem unravels.

Interesting sharing of so many method for solving the problem. In algebraic sense this problem has two variables. Instead of using x and y, or two bars of different lengths for x and y, we can use squares and triangles to represent numbers. In the before situation, E and F each have 1 square. In the after situation, E has 4 triangles and F has 1 triangle. We may change all squares to triangles by replacing a square by a triangle plus 8. We see that a triangle is 24, and then a square is 32.

We may also express squares and triangles in common units, say a square is 4 circles and a triangle is 3 circles. Then we see that a circle is 8, and therefore a square is 32.

These are algebraic method without the use of x and y. We may introduce it as an alternative to the formal algebraic method. Indeed the problem is more appropriate for P5 and above.

Kho Tek Hong - this name sounds quite familiar to me leh, were u one of those who compiled Maths test books sometimes in the late 70s and early 80s?

I was with the Primary Maths Project.

Kho Tek Hong is _the_ Al Guru of Singapore Maths

Don't play play leh, Maths Project Person, i salute Dr Kho Tek Hong Sir

Kho Tek Hong, can accept tan seng hoo as your fb friend? Thank you in advance

tea ceremony plus kowtow 3 times. (just kidding)

We are all friends.

Indeed Dr Kho Tek Hong is the father and pioneer of Singapore Mathematics. Educators have learnt much from him and are still learning.

Ng Foo Keong, can you accept Tan Seng Hoo as your fb friend as u r a jovial guy?

Nice to know that there r so many Maths wiz in this fb maths group helping to answer those who need expln. Yueh Mei u response quite fast to those asking for help. Cheers. As for me i worry my dementia set in n need medical help as this is natural aging

Bro Ng Foo Keong, i like your distinguished unit method as what u explain so clearly, it is very powderful leh, halfway through the solving it unravels or one see light at the other end of tunnel. Very chimèlogy. Good the neh. U just draw very simple graphic to illustrate your workings. I salute to you Bro Ng

This thread has many many Math curriculum experts... Many

Combination of ratio and model...

A quick scribble of the solution... Hope it's clear 😊

Using trail n error method, ratio of R to Y at first is 4:3 or 160 to 120. Since ratio of y now left with 1 part, i started drastically take as given both 110 each R and Y buttons, that give you 50R against 10Y or 5:1 left - but the ans is NOT what the qn ask for, so if you continue further reduce by 115 each then the remaining will be 45R and 5Y meaning the remaing ratio will be 9:1 So since giving 115 each red and yellow buttons (same number of buttons) total given away is 230 since algebra is not recommended and model method some find not easy to digest, i recommend the user friendly Trial n Error merhod.

Thks all....thot of using e trial error but in e essence of time , was thinking e fastest way to complete e qn...

Logically b cos the y buttons left was 1 part, naturally u will think of starting anything more than 100, hope that answers your query

This particular qn can even think as mental sum

*lightbulb lights up*!

I tot my 2 children this method more than 25 years ago + solving thru algebra, i built up their very strong foundation in Maths. I m now a grandpa of 2 n to prevent dementia, i sometimes share some views on those qn on the fb

This is a ratio problem that is categorized as common difference when both quantities reduced by the same amount. Using equivalent ratios, just made their difference before and after the same and you got the answer

Yes u r spot on!

This is basic for anyone who has gone through the training

Cheers

Before R : Y Diff 4: 3. 1u 32u: 24u. 8u After 9u : 1u. 8u So, 32u + 24u = 56u = 280 1u = 5 23u = 23 x 5 = 115

Sorry I forgotten to multiply by 2😅 so should be 115 x 2 = 230

Thank you!

I did it this way

Thank you Mike Tan

5 tarts for $30 so 1tart costs $6 hope u r clear. 7 cakes for $20, so 70cakes = $200, and 35 cakes cost $100 hope this oso clear 2u 140tarts = 140x$6 total cost $840 140 cakes = (35+35+35+35cakes) = $400 bcos 35 cakes cost $100, 140 cakes is made up of 35x4, meaning $100 x4 when u talk in terms of cost. Now u c difference is $440 by taking $840 - $400, but the qn says difference is $550 more and not $440 so we cannot stop here, but u know u r somewhere abt to get correct ans ok So u now take 175Tarts x $6 = $1050 So u take 140 cakes + 35 cakes OR $400 + $100 =$500 for total cost of 175 cakes = $500 Then now we tally with the qn which says bought equal cakes n tarts BUT pay extra or morr by $550 This is done again by very user friendly Trial n Error method