Growingfun Posted January 16, 2015 Share Posted January 16, 2015 My son enjoys math very much. He is working on grade 3/4 math word problems... Sometimes he encounter problems like this.. A boy and a girl collected 24 nuts. The boy collected two times as many nuts as the girl. How many did each collect? He can solve the problem by trial and error using different numbers... For me, it would make sense to use algebraic equation to solve this type of questions...it is fast and accurate... Should I introduce him algebraic method? I am afraid that if I introduce the method too early, it will kill his imagination and creativity. Quote Link to comment Share on other sites More sharing options...
maize Posted January 16, 2015 Share Posted January 16, 2015 Is he using a program like Singapore that teaches bar models? That is how I have seen such problems solved at the elementary level. Quote Link to comment Share on other sites More sharing options...
maize Posted January 16, 2015 Share Posted January 16, 2015 He does not need to resort to trial and error, he needs to interpret the problem in such a way that he can understand the twenty four nuts total could be divided into three equal portions, two going to one child and one to the other. This is where bar models can help. I wouldn't personally want to jump to algebraic expressions if he can't understand on a conceptual level what the problem represents. Quote Link to comment Share on other sites More sharing options...
maize Posted January 16, 2015 Share Posted January 16, 2015 Some bar model examples: http://www.thedailyriff.com/WordProblems.pdf Quote Link to comment Share on other sites More sharing options...
Growingfun Posted January 16, 2015 Author Share Posted January 16, 2015 Thanks for your kind replies. The sample question I used above is not a proper one. The question below is the challenge. A farmer raises rabbits and chickens in a barn. The total head count of animals is 10 and the sum of their feet is 28. How many chickens and rabbits are raised in the barn? He can use trial and error...starting with one chicken and 9 rabbits...until...right combination.. Quote Link to comment Share on other sites More sharing options...
crazyforlatin Posted January 16, 2015 Share Posted January 16, 2015 I think cuisenaire rods really help in these problems. Drawing can be difficult for some kids, but moving rods around would be way easier for them. Quote Link to comment Share on other sites More sharing options...
maize Posted January 16, 2015 Share Posted January 16, 2015 Thanks for your kind replies. The sample question I used above is not a proper one. The question below is the challenge. A farmer raises rabbits and chickens in a barn. The total head count of animals is 10 and the sum of their feet is 28. How many chickens and rabbits are raised in the barn? Here is a solution to a similar problem using bar models: http://www.teach-kids-math-by-model-method.com/excess-value-concept.html Quote Link to comment Share on other sites More sharing options...
maize Posted January 16, 2015 Share Posted January 16, 2015 Personally I would tackle the barnyard problem by viewing it as sets of two legs--if there are 28 legs there are 14 sets of two legs. Since there are only 10 animals, 4 of those sets must be grouped with 4 other sets of 2 to make sets of 4 legs--so there are 4 rabbits. The remaining 6 animals are chickens. To check: 4x4=16 2x6=12 16+12=28 Quote Link to comment Share on other sites More sharing options...
1053 Posted January 16, 2015 Share Posted January 16, 2015 . Quote Link to comment Share on other sites More sharing options...
Kerileanne99 Posted January 16, 2015 Share Posted January 16, 2015 I see no problem introducing the algebraic method. Because we intend to continue with SM (dd is doing 4A at the moment), I first make sure she can use the bar graphs to problem solve. But we are also doing Hands on Equations, and she 'sees' this as a much simpler method:) I actually think it has been very good for her to see and use different approaches to solve the problems! And it definitely stretches her to come up with different approaches. After she is done, she often asks how I might have gone about solving and it is a lot of fun to spark that creativity. Ultimately, you are making sure your child understands the how and the why of solving the problem. The more tools you provide them with, the more they can demonstrate mastery of the material...as well as learn to problem solve via their own creativity. Quote Link to comment Share on other sites More sharing options...
Sherry in OH Posted January 16, 2015 Share Posted January 16, 2015 I think it would be fine to introduce algebraic expression as long as you let him know it is just one way of finding the answer. My first grader’s responses to several of yesterday’s math problems show that he has encountered algebraic expression. For example: ‘Tom has 8 pencils. Ann has 3 times as many as Tom. How many pencils does Ann have?’ The anticipated response (per the lesson plan) was 8 x 3 = 24. His response: [sketch of a pencil] x 8=T T x 3 =A A=24 Quote Link to comment Share on other sites More sharing options...
Staceyshoe Posted January 16, 2015 Share Posted January 16, 2015 Ds1 never "got" the bar diagrams. One day I was helping him with his math and jotted down an algebraic equation to help me figure out what needed to happen in order to solve it. I was going to try to translate that into the bar diagrams (which never came naturally to me either). Ds exclaimed "THAT makes sense!" He had struggled with the bar diagrams for almost a year, and it just didn't click. He immediately understood the algebra without explanation and began solving problems this way. Now that he's doing algebra officially, I'd say it just gave him a headstart with thinking through problems using algebra. I don't really see a downside. Quote Link to comment Share on other sites More sharing options...
kiana Posted January 16, 2015 Share Posted January 16, 2015 I think Hands on Equations is an awesome program for that age. Quote Link to comment Share on other sites More sharing options...
madteaparty Posted January 16, 2015 Share Posted January 16, 2015 I taught the algebraic method because that's the only one I know and didn't want to be bothered with bars. That sort of problemsolving, sometimes now with two different equations, is my DS's strongest area now. Quote Link to comment Share on other sites More sharing options...
avilma Posted January 17, 2015 Share Posted January 17, 2015 I wouldn't call solving the problem by trying all the possible combinations a trial and error method. I would call it the enumeration method and I use it all the time with dd7. That's a vey useful method that is used very often in higher math. In the context of elementary math it helps develop number sense. I think algebraic equations can wait. Quote Link to comment Share on other sites More sharing options...
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