3-4 digit by 2-digit multiplication

Discussion in 'Fourth Grade' started by MrCCES, Mar 16, 2008.

1. MrCCESNew Member

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Mar 16, 2008

I am currently a student teacher in a fourth grade classroom. I am suppose to create a lesson plan to teach my students how to multiply 3-4 digit numbers by 2-digit number. I am desperate for any fun ideas of how to teach it. My mentor teacher keeps telling me that I need to find ways to keep the students engaged. Please respond ASAP!

3. Steph-ernieGroupie

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Mar 16, 2008

I don't know of any "fun" ways to teach that - in my experience, that's one of those things that requires lots and lots of practice. I always start off with a sample problem, let's say 1234 x 56. I show them the expanded form of doing it first - (1234 x 50)+(1234 x 6). We talk about how 56 is 50+6, so I use that knowledge to lead them through the steps of 1234 x 56. Once they have the basic concept down, keep them engaged by having students come up to the board to do problems. Divide girls against boys for who can get more right on the board, or use the groups they're sitting in as teams, etc. Give the same problem to two students, one solves it at the board, and the other on their papers. The one solving it on paper gets to be the teacher who decides if the one on the board was done correctly or not. Have the students work on them individually before showing them at the board, and then have them all give you a thumbs up or down if they think it is correct or not. Just getting them up and out of their seats doing the math problems will do wonders for keeping them engaged in the lesson. Good luck.

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Mar 16, 2008

I've been teaching the same way as Steph. It has worked well. They have to have a very good understanding of the single digit and of place value first. We haven't gone into more than 2 x 2 digit in my class though. We just do lots and lots of practice.

5. RainStormPhenom

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Mar 16, 2008

I've never heard of a way to make it "fun". Remember that "being engaged" and "being fun" are not the same things. Many students think coloring "is fun" but I'd hardly say they are engaged in learning.

Trying to motivate them and encourage them is all I can suggest. "Yes, this is hard, but you are smart and you CAN do it! Let's keep trying!"

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Mar 16, 2008

One "fun" thing I did do, which the kids enjoyed was this:

Three kids work in a group. One rolls four dice and creates 2, 2 digit numbers. One person solves on the white board, and another on the calculator. They check the work. The kids enjoyed this, mostly because we hardly use calculators in class, so it was fun for them!

Most of the time it has been "boring" practice, practice, practice, as it is the only way I know to really be able to get and do these skills efficiently. I did do one lesson on using base-10 blocks with larger numbers to make arrays but it was difficult and confusing to the kids, even though they have used base-10 blocks all their lives.

http://mathcentral.uregina.ca/RR/database/RR.09.98/loewen2.2.html

The lesson I used was something like this.

7. mclaugcrCompanion

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Mar 17, 2008

One way that our district teaches, as part of the Everyday Math program, is called lattice multiplication. If you are able to show the kids a way other than the traditional method, this is a great one because it is a lot easier for the kids to understand. If you don't know lattice, just go to coolmath4kids.com and click on lattice multplication. It shows step-by-step how to do it. Hope this helps!

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Mar 19, 2008

I teach it similarly to the first few posters. However, when I am ready to teach the algorithm, the kids get to use colored pencils. For the example 1234 X 56, the kids choose one color and circle the 1234 and the 6. They do the multiplication in that color. Then they switch to another color and we again loop the 1234, but this time we loop the 5 (which is really 50, so the 6 becomes a zero). They first put the zero down and then multiply again. Switch colors a 3rd time to add the total. It's not really "fun" but it's something different.

9. allydRookie

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Mar 20, 2008

I agree. Teaching multi-digit multiplication is practice, practice, practice. I usually have to spend 3 days on this, depending on my class. One thing that you can do, if you want to impress your mentor and supervisor is be prepared with enrichment for the students that "get it". I will challenge students with either word problems using the skill or adding another digit to the line. I also use Marcy Cook math, if you have that available to use. I usually only have 1 or 2 students that meet that criteria, as we have an enrichment math program at our school. I also require my students to do their multiplication on graph paper to ensure that they are lining up the digits correctly. This helps a lot with the not so neat students, though they will try to put more than one number in each box in the beginning. Good luck!

10. sydelleNew Member

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Mar 23, 2008

I have kind of a fun way to teach it. We do it the American Idol way. I tell the kids that the top line is the judges (I start with a 3 digit number making the analogy to Simon, Paula and Randy). The second line are the contestants. Every contestant gets a turn with each judge ( a turn meaning you multiply). When you multiply, you get the score and it goes down below. When you are done with the first contestant, you have to clean off the stage (erase any carrying marks) and put a 0 down below to keep the scores seperate. For example:
345 x 23 345 are the judges, 23 are the contestants (I line it up vertically of course, I just can't do that here) Starting at the right of the contestants, it's the 3's turn first. He does 3x5 - score below, carry as needed, then 3 x 4, then 3 x 3. Now change contestants. It's the 2's turn. Clear off the garbage, and put the 0 under the first set of scores. Then it's 2x5 2x4 2x5 (all the while putting the scores down and carrying as needed)Now add up the scores and you're done!

I know this seems confusing, but it's really not. It's just regular multi=digit multiplication with a story to go with it. Hope that helps!

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Mar 23, 2008

You could start by teaching them math "tricks" like the power of 1, 10, 100, 1000.... some will pick up the pattern quicker than others. This will also easily lead them into 2d x 3d multiplication.

You can also teach them properties or fact families. You can make a human equation giving each student a card with a number or an symbol.

Once they get a good footing on your method of 2d x 3d multiplication.... show them latice multiplication.

this will give all of them a good number sense when it comes to multiplication and reinforce what was already taught.

12. knitter63Groupie

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Mar 24, 2008

Our district also uses Everyday Math, and my fifth graders LOVE the lattice method. We teach three different strategies: traditional, lattice and partial products. Lattice wins hands down!! Since we switched, I even use the lattice method! It is FUN-and easy!!!

13. Kangaroo22Virtuoso

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Mar 24, 2008

Lattice multiplication is great! A lot of kids that have trouble with organizing the numbers correctly (like forgetting to put in the zero when they are multiplying by the tens number) can get lattice multiplication without a problem. There are also videos on the internet that show lattice multiplication. I just looked quick and this is the one that I found (http://youtube.com/watch?v=xVbzAaJiaxk), but if you search you can find other videos that show lattice multiplication.

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Apr 10, 2008

I'll have to say that I've always taught multiplication the traditional way. We have a math rep from another district as our math liason. They use Everyday Math which our district just adopted for next year. She taught me the lattice math (matrix math) and I felt like something lifted from me helping me see "the light". I immediately taught me students and they love it. At least now they have 2 options to do multiplication with. I'm concerned about all the negative things I've been hearing about Everyday Math. What are your feelings?:huh:

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Apr 12, 2008

After students have been taught this skill, I have a little competition. Four students go to the board at a time. I call out a math problem. The students immediately go to work. When they are completely finished, they turn around. The first one to finish and get the problem correct (must be legible), gets to stay at the board. Three new students come up the board to compete. I only allow the winning student to remain at the board through three rounds.

16. TeachyBonRookie

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May 17, 2008

I LOVE this! Thanks for sharing!

17. Pisces_FishFanatic

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May 17, 2008

So creative!!

18. nc4thRookie

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May 20, 2008

I have created puzzles before where there is a code to break and they have to find the letters that match the answers. For example:

__ __ __ __ __
12 14 32 32 81

E=7x2
H=4x3
L=4x8
O=9x9