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 A to Z Teacher Stuff Forums How do *YOU* teach subtraction with renaming?

#1
12-03-2011, 07:13 PM
 karebear76 Devotee Join Date: Aug 2005 Posts: 982 Ohio Intermed. Intervention Specialist
How do *YOU* teach subtraction with renaming?

I spent several class periods teaching this skill. We used base ten blocks to discover it, I've used all the things I can think of, and now as I grade a few errant papers, I notice that they still don't get it.

I thought most had it, so I moved on to a new concept. Now I see that many more don't have it than do. I'm looking for any and all ideas!

BTW, this is a 4th grade spec ed class, so the more concrete & visual, the better. I'm teaching the same material as the regular math teacher, but spending much more time on each concept.

#2
12-04-2011, 02:36 PM
 waterfall Phenom Join Date: Feb 2011 Posts: 4,797 Western USA K-3 Sped Resource Teacher
By "renaming" do you mean regrouping/borrowing? I've never heard that term before...I want to check that we're talking about the same thing before I answer!
#3
12-04-2011, 04:04 PM
 ciounoi Cohort Join Date: Nov 2009 Posts: 593 Pennsylvania
In student teaching, I used base ten blocks, games, place value order sheets, and whiteboards. I introduced the concept in very, very small increments, like so:

1. Made sure students knew how to use the blocks (some were still shaky)
2. Showed how a ten block could be exchanged for ten one blocks (took a few days)
3. Played a few games to reinforce (mostly just exchanging the blocks for numbers written on my whiteboard)
4. Showed how ten one blocks could be exchanged for one ten block (didn't take much time at all)
5. Played games where they had to make a certain number with the blocks and take a certain number away... basically subtraction w/ regrouping but I walked them through it
6. Introduced the number figures... wrote a lot of things like 23 - 9 = ? on my whiteboard. Kids had to use the blocks to make the numbers and subtract.
7. Did 28349023 practice problems/games to reinforce.
8. Told the kids we were going to try doing the subtraction problems without the blocks, just using the whiteboards and our brains. Some of them got it immediately, some needed lots of reteaching and practice.

I did this until they got it... it took us about 4-5 weeks for almost all of the kids to master. Apparently several of the kids had still not mastered it at the end of the year (I did my unit in the fall)... I guess it just comes with the special ed territory!! :P

Hope this helps!
#4
12-04-2011, 05:21 PM
 karebear76 Devotee Join Date: Aug 2005 Posts: 982 Ohio Intermed. Intervention Specialist
Yes, waterfall, I am referring to regrouping/borrowing. My math methods professor called it renaming as you are renaming tens as ones, hundreds as tens, etc.

Thanks for the tips so far. I'm trying to come up with some new lessons for this...
#5
12-04-2011, 05:27 PM
 Aliceacc Multitudinous Join Date: Apr 2006 Posts: 27,642 NEW YORK Math teacher
Could you tie it into money? Rename \$1 as 10 dimes?? Start the problems with giving change in multiples of 10 cents?
#6
12-04-2011, 05:33 PM
 WaterfallLady Enthusiast Join Date: Aug 2006 Posts: 2,056
Sometimes my students get more confused if I use manipulatives to teach them, or let them use it. Sometimes, I just have to withdraw the concrete manipulatives and show them how to do it. I make a checklist of the steps. They might not get the concept, but if your state requires kids to do it for the test, they can at least do it.
#7
12-04-2011, 05:33 PM
 teacherintexas Aficionado Join Date: Jul 2005 Posts: 3,865 Texas Third Grade Teacher
Have you had the kids draw out the problems in base ten blocks before going to the abstract? When I taught second, several kids had to use that method for much of the year.
#8
12-04-2011, 06:53 PM
 waterfall Phenom Join Date: Feb 2011 Posts: 4,797 Western USA K-3 Sped Resource Teacher
Quote:
 Originally Posted by WaterfallLady Sometimes my students get more confused if I use manipulatives to teach them, or let them use it. Sometimes, I just have to withdraw the concrete manipulatives and show them how to do it. I make a checklist of the steps. They might not get the concept, but if your state requires kids to do it for the test, they can at least do it.
I admit I do this too. The 10's/1's is too abstract. I have a checklist of things they follow as well for multiple digit problems...

1. First check to see if I'm adding/subtracting (most of my kids circle the sign to help them remember)

Once they see they're subtracting...
I always start on this side (farthest from the subtraction sign)
Can I take __(bottom number) things away from ____(top number) things? If you're not sure, get out your fingers. So, "yes, I can take 6 things away from 10. So I keep going" or "no, if I try to take 8 things away from 6 things, I run out. I have to borrow from the other side."

Add your one, and take one away from the other side. Solve. It sounds weird typed out, but it makes sense when you say it when you're looking at the problem, lol.

I've never had a kid not be able to do it after several lessons. They tend to need practice (even when we're doing other concepts, I'll throw a couple of these in at least once every few weeks), but it's not something I really have to spend weeks and weeks on or something.
#9
12-04-2011, 07:26 PM
 Jayneorama Novice Join Date: Nov 2011 Posts: 66 WA Upper Elementary Teacher
Is place value an issue for these kids? For students that have had a hard time with regrouping, I've gone back to basic place value and reviewed/gamed a lot there. Then, when I re-taught the borrowing/regrouping lesson, it went much more smoothly.

I also, aside from all of the manipulative/pictoral teaching, do teach a straight up algorithm - I use a modified Knockin' On Heaven's Door, "Knock, knock, knockin' on my neighbor's door, to borrow 10," to remind them of procedure and make it fun. There are some kids, in my experience, who get the concept but not the procedure until they are explicitly taught the algorithm.

I have no idea what would or would not apply to SPED in this case, so your mileage may vary here.
#10
12-04-2011, 07:34 PM
 karebear76 Devotee Join Date: Aug 2005 Posts: 982 Ohio Intermed. Intervention Specialist
Thanks for all the suggestions! Lots of good ideas here.

We spent about a month at the beginning of the year with place value, and most have a basic to good understanding of it. We've been going over some of the most difficult things IMO to teach all in the name of a test: place value to hundred millions, rounding to nearest million, subtraction with renaming, and estimating sums and differences (through millions)...

I have at least 5 different ability levels at the same time.

I really don't like teaching math much this year

 Tags renaming, subtraction, teach

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