Rectangular Arrays to Teach Multiplication
Date: Thu, 10 Nov 1994 12:28:42 -0700 (MST) From: Anonymous Subject: multiplication I'm Glen, hi! I teach fourth grade math. Are rectangular arrays the best way to teach multiplication? Thanks for your time.
Date: Thu, 10 Nov 1994 16:10:13 -0500 (EST) From: Dr. Ken Subject: Re: multiplication Hello there, Glen! Well, I'm not sure we're really your best resource on this question. I'm happy to tell you my opinion, but I've never been a math teacher nor have I graduated from college yet, so I may not be of much help to you. I think that it's very important for students to see the relationship between addition and multiplication, i.e. that mulitiplying 7 by 5 is the same thing as adding seven fives together. And let them discover (lead them to it if they need some help) that adding seven fives together will give you the same result as adding five sevens together. I mean, that's a pretty deep result for a fourth-grader. I know I was excited. I think that using rectangular arrays is a good way to visualize mulitiplication, but I also think that kids should be well-grounded in symbol manipulation, i.e. writing out 7 + 7 + 7 + 7 + 7 and seeing that it equals 35. Gaining familiarity with this kind of manipulation will help them when they start to learn Algebraic manipulation of variables. Of course, these are just a couple of ideas. Perhaps another Math Doctor will have other ideas. -Ken "Dr." Math
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