I said in this post that I'd be writing more about what both Brian and Sean are encountering when doing Singapore Math. I guess I haven't done much of that, have I? Actually, I think I haven't done ANY of that!
I did start a private blog (work in progress) in June, some months after I wrote that post, but that effort quickly fizzled out. However, in the past week (since Oct 11), I've been more productive, uploading questions and solutions; I am indeed Master Procrastinator, I had Brian's birthday and my Japan trip to plan and suitcases to pack, but I'd rather work on a Math blog!
Monica's the model mum, I'm not; we're just muddling our way through. I give up really quickly with many of these questions. I'm pretty sure the 'model' in our solutions is not standard, so any help is welcome in guiding us the right way.
I've just found out from a Singapore friend that the Math test for students returning from overseas (to get into secondary schools) is as tough as PSLE. Her daughter sat for the exams this past week, and there were 2000 kids in Expo, including Chinese, Korean, Japanese, and Indian kids. I was under the impression that overseas kids would not be expected to do PSLE-standard math, since they've not exposed to the methods taught to Singapore students.
So here we go: From P5 Challenging Math, Unit 1, No 23 (Challenge question, no solution provided). Just checked, this was not the Challenge question, and there was a solution provided but it looked like algebra to me.
A basket of 6 apples and 3 mangoes weighed 1kg320g. After 4 apples and 2 mangoes were eaten, the basket with the remaining fruits weighed 760g only. If a mango weighs 20g less than 4 times the mass of an apple, find
a) the mass of the basket,
b) the mass of the apple.
My model. Okaylah, can skip reading my attempt, I'm so rubbish at this I'm confused when I see my solution now!
m+20=4a -> m=4a-20----------(3)
Substitute (3) into (1) and (2)
Substitute (4)into (5)
Substitue (6) into (5)
The mass of the basket is 480g
The mass of the apple is 50g
Is either of my model or Brian's acceptable? I'm sure there's a simpler way to present the model, so this is kind of an SOS out to all model moms and their kids out there. Thanks in advance.
Solutions may be sent to mathsingapore at gmail dot com. Thanks!