# Long Division

Discussion in 'Elementary Education' started by S Dubb, Apr 30, 2010.

Joined:
Jan 7, 2007
Messages:
281
0

Apr 30, 2010

My third graders are set to learn this next week and I was just wondering if anyone had any helpful/neat/fun/engaging tips for helping kids remember all the steps for this daunting task. Isn't there some sort of mnemonic for long division?

3. ### DaleJr88AmpFanCohort

Joined:
Apr 19, 2008
Messages:
565
0

Apr 30, 2010

I use the DIVISION HOUSE...

In the division house, there lives a family who likes to divide.
Mommy says, "Multiply".
Sister says, "Subtract".
Cat says, "Compare".
Brother says, "Bring down".
Dog says, "Do it all over again".

Hope that helps...

4. ### MissJillCohort

Joined:
Jul 30, 2009
Messages:
733
1

Apr 30, 2010

We sing, divide, multiply, subtract, bring down! with hand motions.

5. ### ToakCohort

Joined:
Jan 9, 2010
Messages:
555
1

Apr 30, 2010

Does Mary salt cold rigatoni

6. ### AliceaccMultitudinous

Joined:
Apr 12, 2006
Messages:
27,534
6

May 1, 2010

Let's see if I can remember my daughter's (she's still asleep)

Does Mcdonalds Serve Burgers, Really?

Divide, Multiply, Subtract, Bring down, Repeat.

7. ### MrsCMultitudinous

Joined:
Aug 8, 2005
Messages:
14,033
1,853

May 1, 2010

Some that my students have used in the past:
Dracula must suck blood.
Does McDonalds Sell Burgers?

8. ### shouldbeasleepEnthusiast

Joined:
Jul 28, 2007
Messages:
2,233
0

May 2, 2010

I am an advocate of short division. It's so much more simple.

http://www.themathpage.com/arith/divide-whole-numbers.htm

Only I call it "remainder" or "left over" division.
I tell them to write the remainder (what's left over) beside the next number, underline both of them and then divide into it. Put the answer above, and write the remainder down beside the next number.

It's just so much easier than trying to remember all of the steps. And mathematically, it makes sense. You are trying to see how many times something will go into something with how many left over instead of trying to remember to subtract then bring down. And with a huge number, the student doesn't get lost because of writing crookedly.

But if you do decide to go with long division, have them use graph paper so that the number columns stay straight. Or they can turn lined paper sideways.

9. ### AliceaccMultitudinous

Joined:
Apr 12, 2006
Messages:
27,534
6

May 2, 2010

Long Division skills will be necessary in Algebra when they divide polynomials. Not having the skills means they're sure to have a problem down the road. Short division won't cut it.

10. ### ShanooHabitué

Joined:
Oct 28, 2007
Messages:
761
5

May 2, 2010

I went to a math workshop last week where the facilitator (Trevor Brown) said that the only multiples kids needed to know for long division was multiples of 1, 2, 5 and 10. If they could multiply by those numbers, they could divide.

So, if we have 350 and the kid wants to divide by 11:

We know that 11 times 10 is 110, so subtract 110 from 350 and mark the 10 down in a list off to the side.

350 - 110 = 140

Now we do the same thing over again.

11 times 10 is 110 so subtract that from 140. Mark another 10 down in the list off to the side.

140 - 110 = 30

Now, do it one more time:

11 times 2 is 22. Subtract that from 30 and mark the 2 down on the side.

30 - 22 = 8

10 + 10 + 2 = 22

So, we know that 350 divided by 11 equals 22 remainder 8

I teach high school, but the lower grade teachers really seemed to like it a lot!!

11. ### AliceaccMultitudinous

Joined:
Apr 12, 2006
Messages:
27,534
6

May 2, 2010

But, again: that system won't prepare them for high school math.

Knowing only limited math facts is going to be a REAL issue when that student hits factoring trinomials!!!!

Joined:
Jan 23, 2009
Messages:
380
0

May 2, 2010

I teach fourth and starting at the beginning of the year I do multiplication and division every Monday. When I start teaching long division I teach the scaffold method.

Here's a link for an explanation..Scroll down for division:

http://www.teachingk-8.com/archives...re_fun_with_algorithms_by_michael_naylor.html

As the year goes on I transition them to the traditional algorithm. When I transition them, I use the scaffold method first and then I do it the traditional method right next to it, so they can see where all my numbers are coming from. I think this really helped and my kids have a strong understanding of division and they don't just go through the motions.

I also do this with multiplication.. We break down numbers and then multiply.

13. ### mmswmModerator

Joined:
Nov 5, 2007
Messages:
5,621
6

May 2, 2010

I just have to wonder...what's wrong with teaching WHY the traditional algorithms work? They make far more sense mathematically than some of these mental math algorithms that are trying to pass for real math, and they don't set up students for failure later on. Granted, I don't have a problem with mental math, but I think it's ultimately harmful to the students to not have a thourough understanding of the traditional algorithms and the reasons why they work. There's a reason why they're "traditional". Wouldn't it be better to spend the time teaching the why's instead of teaching kids methods that will untimately become a hinderence to them?

14. ### AliceaccMultitudinous

Joined:
Apr 12, 2006
Messages:
27,534
6

May 2, 2010

...or at least keeping an eye on the big picture? Not limiting our kids to this year's standards, but keeping an eye on WHY something "has always" been taught the way it has.. because down the road they'll need the foundation??

Joined:
Apr 7, 2005
Messages:
3,231
66

May 2, 2010

It's funny you say that, because around here at least, mental math would actually be understanding the algorithms. It's not until you truly understand the WHY that you can figure out shortcuts that will also work. At least, that's what I think.

16. ### mmswmModerator

Joined:
Nov 5, 2007
Messages:
5,621
6

May 2, 2010

But, as the failure of our secondary students indicates, it just doesn't work that way.

Joined:
Jan 23, 2009
Messages:
380
0

May 2, 2010

I teach both methods, so my kids leave my classroom knowing both.. However, they prefer the traditional method in the end.

Joined:
Apr 7, 2005
Messages:
3,231
66

May 2, 2010

Oh I agree with you. Perhaps instead of looking at mental math as a means to an end, we need to look at mental math as an end (or maybe a better term would be a "goal"... I suppose we don't just want to end there) in itself?

So rather than teaching metnal math strategies, we focus on teaching the "why" and then from there, we can show why some of our common mental math strategies work.

I can't tell you how excited I was coming back from a Learning Disabilities conference in my first year that talked all about Math, and showed some strategies to help students... So much stuff finally clicked, as far as the shortcuts we take in the simple operations. I was always very good in Math, but I finally figured all that stuff out!

Geez... all this talk about Math may have me excited again about applying for the Math mentor position at my school next year...

19. ### AliceaccMultitudinous

Joined:
Apr 12, 2006
Messages:
27,534
6

May 2, 2010

Do it. You are the kind of teacher we need in those positions!!

Joined:
Apr 7, 2005
Messages:
3,231
66

May 2, 2010

But I love teaching Literacy so much now!!! :lol:

I'll send the Math guy at the district an e-mail for starters.

Joined:
Jan 7, 2007
Messages:
281
0

May 2, 2010

Thank you for all the links, but I'm also afraid that the "shortcuts" will just confuse them even more. I'm looking to teach them the traditional way, but with little hints and tips while doing so. I also believe that they just need to know why it's done the way it is. Once they do know that, then maybe the little shortcuts will have a place in the curriculum. With something so cut-and-dry as math facts though, I think knowing the "long way" is key.

I really hope that didn't come across as ungrateful, because I certainly appreciate the links. Right now I think I'm sticking with mnemonics for the only "tip" at the moment.

22. ### AliceaccMultitudinous

Joined:
Apr 12, 2006
Messages:
27,534
6

May 2, 2010

No, you didn't come off as ungrateful at all.

And once kids understand the process, mnemonics can help them remember-- my Sophs are the kings and queens of SOHCAHTOA!

Joined:
Jan 23, 2009
Messages:
380
0

May 2, 2010

You have to do what's right for you students..You know them best! Since I start teaching multiplication and division so early in the year I can teach the scaffold and traditional method.

24. ### MissKH81Rookie

Joined:
Oct 31, 2007
Messages:
92
0

May 2, 2010

I, too, find that the mnemonic device about the fun sentences work best. I find it interesting that no one mentioned this tip:

Your kids MUST MUST MUST know their basic multiplication/division facts frontward and backward at the click of a finger before you teach long division!

I give timed multiplication tests that my students must pass with an A before moving on to the next timed test. Every year I have at least one parent who fights me on these timed tests. It's not until we do long division that they actually FULLY UNDERSTAND why I do those timed tests. You will not be able to do long division without the basics. It sounds like common sense,but it's the most important truth about learning this concept!

25. ### TeacherGroupieModerator

Joined:
May 13, 2005
Messages:
29,779
1,160

May 2, 2010

Welcome to our choir, MissKH81: mm and Alice (and I too) make precisely this point with great regularity.

26. ### AliceaccMultitudinous

Joined:
Apr 12, 2006
Messages:
27,534
6

May 2, 2010

TG, did you just call me a nag?

27. ### mmswmModerator

Joined:
Nov 5, 2007
Messages:
5,621
6

May 2, 2010

She lumped me into that group too. :lol: I prefer to focus on the "choir" part of that statement.

Joined:
Apr 7, 2005
Messages:
3,231
66

May 2, 2010

Nah, i think she just called you regular. Which is much better than the alternative...

29. ### mmswmModerator

Joined:
Nov 5, 2007
Messages:
5,621
6

May 2, 2010

dflemming...what did you decide about the math mentor position?

Sorry.

Joined:
Apr 7, 2005
Messages:
3,231
66

May 2, 2010

I'm going to send an e-mail out tomorrow. I really don't think they'll give it to me anyway, as I think they'd prefer to have a more seasoned teacher in the role... but it's not like it could hurt.

31. ### mmswmModerator

Joined:
Nov 5, 2007
Messages:
5,621
6

May 2, 2010

Good luck with it! I know you're torn between literacy and math. Sometimes we just don't know what we're best at, and love, before we do it. I hope it turns out to be great for you

Joined:
May 13, 2005
Messages:
29,779