jenniferlee Posted January 10, 2011 Share Posted January 10, 2011 Man, this makes me feel so thick... Here it is: Ali sold 5 toasters and 3 rice cookers for 500.00 If a rice cooker cost $20 less than a toaster, find the cost of a rice cooker. We are all stumped. And this is the last problem to finish the book, so we couldn't just let it go :) Thanks Jen Quote Link to comment Share on other sites More sharing options...
swainsonshawk Posted January 10, 2011 Share Posted January 10, 2011 Okay, I like Singapore math bar problems! I switched around the statement that the rice cookers were $20 less than the toasters, and I thought to my self that the toasters were $20 more that the rice cookers. So my toaster line on the bar graph included 5 boxes for 5 toasters, plus 1 box equalling $100--the total of the extra money that the toasters cost. I subtracted this 100 from the 500 that it all cost all together, getting $400. Then I divided that $400 by 8 (the total items purchased), finding out that each box equals $50. Adding back in the 20 difference to the toasters, the toasters cost $70 each and the rice cookers cost $50. Fun! Quote Link to comment Share on other sites More sharing options...
NicksMama-Zack's Mama Too Posted January 10, 2011 Share Posted January 10, 2011 (edited) Man, this makes me feel so thick... Here it is: Ali sold 5 toasters and 3 rice cookers for 500.00 If a rice cooker cost $20 less than a toaster, find the cost of a rice cooker. We are all stumped. And this is the last problem to finish the book, so we couldn't just let it go :) Thanks Jen 5 toasters [________] {+ 20 } [________] {+ 20 } [________] {+ 20 } [________] {+ 20 } [________] {+ 20 } 3 rice cookers [________] [________] [________] total = $500 $500-100 = $400 spread over 8 units. So $400/8 = $50 So the rice cookers cost $50 each and the toasters $70 each. The most important fact to keep in mind is that the rice cooker and the toaster cost the same up to a point and then the toaster cost $20 extra. So you try to find the common unit by setting it up as I have (these could be bars, but I tried to make it work on these boards). Edited January 10, 2011 by NicksMama-Zack's Mama Too Quote Link to comment Share on other sites More sharing options...
jenniferlee Posted January 10, 2011 Author Share Posted January 10, 2011 Thank you! And my son thanks you! We tried subtracting $60 from the total for the three rice cookers and it just wasn't working. Obviously thinking backwards Jen Quote Link to comment Share on other sites More sharing options...
musicianmom Posted January 10, 2011 Share Posted January 10, 2011 This is what I don't quite get about Singapore math. To me, this is an algebra problem. I did it as: 5(x+20) + 3x = 500 What level book was this problem in?? Quote Link to comment Share on other sites More sharing options...
ondreeuh Posted January 10, 2011 Share Posted January 10, 2011 This is how I just did it too, and I don't even use Singapore. Which book was this in? Quote Link to comment Share on other sites More sharing options...
Testimony Posted January 10, 2011 Share Posted January 10, 2011 If 1 rice cooker costs x, and a toaster costs $20 more than a rice cooker, then 5 toasters and 3 rice cookers cost 8x +100= $500. 8x=$400 $400/8= $50 $50 is the answer. An alternative is Rice cooker is [(x-$20)x5]+3x=8x-$100=$500=$400=8x=400/8=$50 $50 is the answer. From, Gabriel the son of Karen http://www.homeschoolblogger.com/thegenius or Karen's blog at http://www.homeschoolblogger.com/testimony Quote Link to comment Share on other sites More sharing options...
siloam Posted January 10, 2011 Share Posted January 10, 2011 This is what I don't quite get about Singapore math. To me, this is an algebra problem. I did it as: 5(x+20) + 3x = 500 What level book was this problem in?? The point is to develop a deeper thinking in math. The difference between US and Asian math teachers is often the US teacher have more education into Calculus, but less ability to apply math. Asian teachers have less instruction (often just basic math for elementary teachers), but they routinely work on applying what they do know to higher level situations, thus their understanding of and ability to apply math is deeper. I don't know exactly what book this was in, but Singapore starts these problems in level 3 and continues through level 6. My guess this one was in book 4 or 5. Heather Quote Link to comment Share on other sites More sharing options...
JeneralMom Posted January 10, 2011 Share Posted January 10, 2011 I have to admit, I have trouble with the whole bar graph thing because my mind immediately jumps to Algebra to solve these problems. We love Singapore math so I guess I will just have to suck it up when we get to it. Quote Link to comment Share on other sites More sharing options...
jenniferlee Posted January 10, 2011 Author Share Posted January 10, 2011 yes, the last page of 5A We've worked through many other problems like this using the bar diagrams. Usually my son has no problem getting them, this one stumped us for some reason. I don't have the teachers manual or answer key. I've only had one other problem this year I couldn't get on my own, so I haven't bothered. Quote Link to comment Share on other sites More sharing options...
Dana Posted January 10, 2011 Share Posted January 10, 2011 I have to admit, I have trouble with the whole bar graph thing because my mind immediately jumps to Algebra to solve these problems. We love Singapore math so I guess I will just have to suck it up when we get to it. :iagree: I teach algebra and am very used to teaching "how to solve word problems" in certain ways. Using bar models has been a shift in my thinking. What's really cool though is how the bar models will help ease the transition to algebra. I can see how my son will have a lot less trouble with word problems than I did from a solid familiarity with the model approach. There are also some problems I've run across (Bk 3) that are significantly easier to solve with bar models than algebra! However, I have reached the point where I'm working the problems in the CWP so I've got the model for the solution and not just the solution. It does take time... :glare: Quote Link to comment Share on other sites More sharing options...
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