tag:blogger.com,1999:blog-6746419206932469118.post4587821697630174050..comments2023-09-23T19:03:39.693+08:00Comments on Road to PSLE: Henry Park Pri Sch 2007 PSLE Math Prelim Q48Excel Eduservicehttp://www.blogger.com/profile/11691081348489781290noreply@blogger.comBlogger9125tag:blogger.com,1999:blog-6746419206932469118.post-44232934613063683962008-09-06T13:13:00.000+08:002008-09-06T13:13:00.000+08:00It is not quite right to say that is algebra. Alge...It is not quite right to say that is algebra. Algebra has very specific rules. Example, a x b = ab. On the other hand, there is no such thing as apples x oranges = applesoranges in models. <BR/><BR/>Many people who have not taught PSLE Maths get the wrong concept that algebra is used in models. While some of the principles used are similar, it is wrong to say that algebra has been used. Algebra is a specific topic, with its own rules, which models cannot follow in totality.Excel Eduservicehttps://www.blogger.com/profile/11691081348489781290noreply@blogger.comtag:blogger.com,1999:blog-6746419206932469118.post-16622558842566737782008-09-06T10:05:00.000+08:002008-09-06T10:05:00.000+08:00In P5, pupils are already using algebra to solve t...In P5, pupils are already using algebra to solve their problem sums (although they were not told that it is algebra). Eg<BR/><BR/>3 Apples + 2 Oranges --> $2.00<BR/>2 Apples + 3 Oranges --> $2.50<BR/><BR/>6 Apples + 4 Oranges --> $4.00<BR/>6 Apples + 9 Oranges --> $7.50<BR/><BR/>5 Oranges --> $3.50<BR/>1 Orange --> $0.70<BR/><BR/>3 Oranges --> $2.10<BR/><BR/>2 Apples --> 2.50 - 2.10 = $0.40<BR/>1 Appple --> $0.20Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6746419206932469118.post-50308693515497223762008-09-05T17:13:00.000+08:002008-09-05T17:13:00.000+08:00Let me try to explain how 15 units are derived.DV ...Let me try to explain how 15 units are derived.<BR/><BR/>DV DL DC<BR/>----------<BR/>3 : 4 : 6<BR/><BR/>As the distance is the same, make them the same 3 x 5 --> 15 and 5 x 3 --> 15, <BR/>DV DL DC<BR/>----------<BR/>1 : 2 = 5 : 10<BR/> 2 : 3 = 6 : 9<BR/>----------<BR/><BR/>In this case, 1 unit is the distance covered by the car in 2 minutes and total distance is 10 units.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6746419206932469118.post-13082774062034588292008-09-05T17:00:00.000+08:002008-09-05T17:00:00.000+08:00My sincere apology, the workings for part b is cor...My sincere apology, the workings for part b is correct. But we could have made use of the answer to part a to work out part b instead of having to figure out a different 15 units.<BR/><BR/>DV : DL : DC = 3 : 4 : 6<BR/><BR/>1 unit (DL - DV) --> (60 + 120) x (2/60) = 6 km (Distance covered by Van and Car in 2 minutes) <BR/><BR/>Total distance: 10 units (DL + DC) --> 10 X 6 = 60 km.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6746419206932469118.post-24521193821607170762008-09-05T16:04:00.000+08:002008-09-05T16:04:00.000+08:00I am afraid although the answer to part b is corre...I am afraid although the answer to part b is correct, the workings do not seem quite right. <BR/><BR/>Based on your drawing, for the 2 minutes, the distance is covered by both the lorry and the car and not the car alone. So it should have been<BR/><BR/>(60 + 120) km/h x (2/60 h) = 6 km.<BR/><BR/>6 km is 1 unit <BR/>From part a), this is the difference in distance between the van and the lorry (4 units - 3 units)<BR/><BR/>Total distance is 10 units (the combined distance covered by the van and car)<BR/>1 unit --> 6 km<BR/>Total distance (10 units) --> 60 kmAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6746419206932469118.post-80571445782332640552008-08-27T23:07:00.000+08:002008-08-27T23:07:00.000+08:00P6 students are not trained to use algebra to work...P6 students are <B>not</B> trained to use algebra to work out speed sums. <BR/><BR/>The 15 units is based on trial and error, which is actually guess and check - an accepted method in PSLE Math.Excel Eduservicehttps://www.blogger.com/profile/11691081348489781290noreply@blogger.comtag:blogger.com,1999:blog-6746419206932469118.post-69307953135246733652008-08-27T16:27:00.000+08:002008-08-27T16:27:00.000+08:00it doesn't shows how you obtained 15 units, or how...it doesn't shows how you obtained 15 units, or how you arrive at the model diagram (of total 15 units) - like why the van covers 6 units. The best method would be to use algebra. That is, 1/2 (x + 4) + 4 = 2/3x, where x is the distance the car meets the van.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6746419206932469118.post-26540168497239156662008-07-31T15:51:00.000+08:002008-07-31T15:51:00.000+08:00The way to do it is to read and refer to the graph...The way to do it is to read and refer to the graph while you read. I know it is a little difficult scrolling up and down, but that is the inherent problem learning from the computer screen.<BR/><BR/>I have highlighted this point before, that computers can never replace the board as far as teaching is concerned. <BR/><BR/>The ideal is still traditional face to face learning. If the computer can replace teachers, MOE would have done that a long time ago. Training teachers is not cheap. It costs the government (and your tax money) quite a bomb.Excel Eduservicehttps://www.blogger.com/profile/11691081348489781290noreply@blogger.comtag:blogger.com,1999:blog-6746419206932469118.post-68800901301527953622008-07-31T13:54:00.000+08:002008-07-31T13:54:00.000+08:00you are only confusing the students.you are only confusing the students.Anonymousnoreply@blogger.com