So, I'm thinking about just teaching lattice method for how to multiply large numbers. Is this wise? The reason behind this decision is that last year, I taught both ways. The kids who did the "regular" old way mostly had bad scores on the tests because they never could remember those rote rules of "bringing down a zero", etc. The kids who learned through lattice did much better. Any opinions or advice?

I know that our middle schools won't allow students to use the lattice method for multiplication (why, I do not know.) So we have to make sure our fifth graders know the traditional method. If a student doesn't "show his work" using the traditional method in middle school, they are marked as "wrong" even if they get the right answer. Confuses the heck out of me why they do this, but they do.

I think you should teach both because "everyone else" does it the "normal way." I think they need both.

Ask the 6th grade teachers what they prefer...and if they want the old fashioned way, then I would teach it. If not, teach what they are comfortable with and would be successful. Everyday math is about options for students-that is why it is so popular. Honestly, how many adults go through the old fashioned way? Most grab the trusty calculator.

I would teach both, just because I always have that one or two that get the old fashioned way better. Plus, parents tend to rely on that method when reviewing homework with their children. I personally love lattice, and use it myself now. But having both options will probably serve the children better.

The rule of bringing down the zero is as far from "rote" as counting apples. If the kids realize that it's a place value thing, then maybe they might understand it better. Of course, most adults were taught the standard algorithm by rote and don't realize it themselves, but, there is actually a very firm, non-rote reason why it is done that way in the traditional algorithm. Maybe you could incorperate a place value investigation into the traditional way.

I taught both and now that I'm teaching 6th grade math I let the kids use whatever they understand. In the "real world" (ie=grocery shopping...) they aren't going to be told that HAVE to do it a certain way so I let them pick.

Have you tried the "all partials" method. I love it and it really reinforces place value. I've also shown them base ten shorthand, but it is only feasible times a one digit number or a very low two digit number. Middle school requires the algorithm I know, but I use the rule "If you can't explain it, you can't use it" Try showing them with base ten blocks WHY the zero is placed where it is in the algorithm method.

Multiplying decimals gets tricky with the lattice method. We use EDM and try to teach the "standard" method in 5th grade.

Why do you think it is tricky with multiplying decimals? My students are multiplying decimals right now, and most of them are using lattice? No one has had any problems. Just curious.

I agree with the above posters about teaching both. Lattice is a sound method, but parents and future teachers may take issue with it as the only method taught. Do you have a math curriculum specialist for your district that you could ask? At our HS professional day a few weeks ago, we actually discussed a similar situation where long division was not being taught by some teachers, which later hurt those students in Algebra 2 and beyond with polynomial division.

I am actually thinking of teaching Lattice multiplication for the first time this year because it seems as if my students (5th graders) might "get it" alot easier than the traditional way. Multi-step multiplication is ALWAYS an area that a lot of my students have struggled with through the year, and just recently I was looking into different techniques. I found the lattice method, tried it myself, and LOVED it. I do, however, want to teach the traditional way still, then lattice, and giving them the choice. Let me know how teaching them JUST lattice works- does everyone get it? Are they stuck on the traditional way? I am intrigued. Thanks so much

I hate to admit my ignorance, but what IS the lattice method? And, if that's all they know, will they be able to multiply polynomials when they hit high school? Or is the short term gain setting them up for future failure?

Yes...they will not be able to multiply polynomials, or factor, or do symthetic division. I can't explain the lattice method because I've only seen it once, and it seemed to me it was simply codifying mental math with a somewhat more complex and mistake prone algorithm that's somehow supposed to be better than the traditional algorithm. I'm sorry to anybody who likes it, but I'd rather teachers spent time teaching place value and the base ten system along with the traditional algorithm so that students will actually have something to think back to when they have to learn the stuff that's based on the traditional.

That's how it was starting to sound to me. It seems to me that, as teachers, we've GOT to keep an eye on the future. If I show my kids all the shortcuts in the world, but don't teach them a basic understanding of the fundamentals, then I'm doing them no favor. It only means that later on they'll end up missing the basic skills their peers have. I can't tell you the number of times I've said already to my classes: "When I'm Queen of the Universe, here's what I'll change..." (And remember, I missed a month of school!!!!) Too many kids come in with all sorts of shortcuts and semi-understanding of things. Then they hit a brick wall when those shortcuts don't hold up to the upper level coursework. They end up feeling stupid because they don't understand concepts their peers learned years ago.

I don't disagree with what mmswm and aliceacc are saying, but when your district has adopted this math program, and the administration is placing more on your plate than the clock will allow in one day, I have to make a choice. I teach the program that is adopted. I do agree that we have to look to the future, but for the past 2 decades the education system in this country has continued to "dumb down" the standards we have to teach. Does it stink for middle school and high school math teachers? I am sure it does. The same way it stinks for the 5th grade teachers who have a room full of students who still can't add or subtract, let alone know the basic multiplication tables. Let's hope that with the new president elect, change really will happen.

I think it needs to start at the grass roots, not at the top. Parents need to react when their kids aren't being taught script, or made to memorize their times tables, or don't understand the basics. Teachers and prinicipals-- those on the front lines who see what's happening-- need to speak up as these new "fluff" programs are being adopted. Someone at the local level is making these decisions. That person needs to be made aware that the decisions are not in the long term best interests of the kids.

There's an explanation of the lattice method at http://www.answers.com/topic/multiplication-algorithm; it's noted that the lattice method is algorithmically equivalent to regular multiplication; seems it originated with Fibonacci and that it's what underlies Napier's bones. So it isn't exactly that the lattice method is a shortcut so much as that it's a different way to visualize the standard process or something very like it.