mamamindy Posted August 12, 2013 Share Posted August 12, 2013 We're using SM 1a and we're at the section of subtraction from a two digit number by subtracting the ones, like 18 - 5 = 13 My DD just turned 6, and has seemed to get conceptual math really well at this point. However, she seems to resist subtracting from the ones... and if I set up the problem getting her to subtract from the ones, she will come up with the answer of 3, instead of 13. She understands place value. We use c-rods almost exclusively. (She resists other manipulative, but that may be just because I prefer c-rods...?) Any suggestions for me? I need some other methods of demonstrating this to her because I only have the ones in the IG. It's just not clicking yet. Quote Link to comment Share on other sites More sharing options...
go_go_gadget Posted August 12, 2013 Share Posted August 12, 2013 I've used SM 2&3, but not 1, so I'm not sure they teach subtraction. Is she really solid on the number bonds? For instance, mine would look at 18-5 and think ''Eight is five and three, so 18-5 has a ten and a three 'leftover', so that's 13''. How would she add 13+5? Quote Link to comment Share on other sites More sharing options...
boscopup Posted August 12, 2013 Share Posted August 12, 2013 Is she able to do it with the c-rods? If so, let her keep doing that. It will click eventually. You'll also get more practice in 1B. Quote Link to comment Share on other sites More sharing options...
mamamindy Posted August 12, 2013 Author Share Posted August 12, 2013 She does seem to get the number bonds...but likes using the c-rods. Yes, she gets it with the c-rods, but doesn't it do it the way it says in the book, taking away from the ones. Seems as if she did, she'd be able to visualize it better. We'll keep going. This is the first time she's said "math is hard" yadda yadda. Quote Link to comment Share on other sites More sharing options...
mamamindy Posted August 12, 2013 Author Share Posted August 12, 2013 Funny, we're in 1B with her sister, and she's getting stuck on subtraction as well. I may play some game with them, relax it a bit, and I bet it will click soon. Thanks again! :) Quote Link to comment Share on other sites More sharing options...
Monica_in_Switzerland Posted August 12, 2013 Share Posted August 12, 2013 If she's doing it correclty when using the rods, I'd just keep letting her use them. As numbers got bigger, we moved to doing subratction by stacking the subracted number on top of the whole, so for 18-5, I'd set the 10 and 8 next to each other, but not lined up, if that makes sense, then stack the 5 and show that since it "fits" over the 8, we can subtract direclty from the 8. When you move on to subtraction with borrowing (i.e. 13-5) you can place the 5 over the 3 and see that there isn't enough and that you need to stack it over the 10 instead, making the final problem more like this: 13 - 5 10 - 5 + 3 8 So if your daughter is currently trying to subtract from the 10 when it's not necessary (no borrowing needed), maybe let her know that later on you will subtract from the ten when there are not enough ones. Maybe she'll do it your way if she knows she gets to do it her way later. :-) Quote Link to comment Share on other sites More sharing options...
letsplaymath Posted August 12, 2013 Share Posted August 12, 2013 I once heard a math professor say, "The cool thing about math is that, even when there's only one right answer, there's never only one way to solve the problem." If her way is working for her, then I wouldn't fight it. I would make sure she also understood the book's way, but then let her work the problems however she likes. Especially if she's somewhat stubborn, like my daughter, she may come up with some really strange ways to work at times -- but at least she's learning! Quote Link to comment Share on other sites More sharing options...
mamamindy Posted August 13, 2013 Author Share Posted August 13, 2013 I once heard a math professor say, "The cool thing about math is that, even when there's only one right answer, there's never only one way to solve the problem." If her way is working for her, then I wouldn't fight it. I would make sure she also understood the book's way, but then let her work the problems however she likes. Especially if she's somewhat stubborn, like my daughter, she may come up with some really strange ways to work at times -- but at least she's learning! Thanks! And I love what the math professor said! I just want her to understand - I certainly never did growing up and I"m still learning. She's actually not stubborn at all, very tender and sensitive. She actually had her first cry at "school time" because she didn't understand what I was asking of her... I felt terrible!!! Sometimes the singapore way is NOT intuitive. We'll go slow. Thanks again. :) Quote Link to comment Share on other sites More sharing options...
Guest Posted August 13, 2013 Share Posted August 13, 2013 1B was a big stumbling block for us; we left the program, lol. (But then came back...twice!) Hang in there! Quote Link to comment Share on other sites More sharing options...
Tanikit Posted August 13, 2013 Share Posted August 13, 2013 I see no problem if she subtracts from the 10 - I had to reteach my DD when it got to the regrouping as she kept wanting to take from the smaller number and then the additional from the 10 which took her longer to do. She now knows all the methods and is free to choose whichever she wants. Subtraction was more difficult for my DD than addition for some reason and she seemed to use manipulatives with it for longer than for addition also (she still does) Quote Link to comment Share on other sites More sharing options...
Incognito Posted August 13, 2013 Share Posted August 13, 2013 Do you put it in terms of cookies/candies? I find my kids understand subtraction and addition amazingly well when applied to something they really care about. For instance, if she thinks the answer is 3, ask her if she really only has 3 candies left when you take 5 away. If she understands the concept, she's probably just missing you on semantics when you are telling her to just subtract the ones and then you are saying she is wrong when she doesn't include the tens in her answer. Just my take, of course. Quote Link to comment Share on other sites More sharing options...
mamamindy Posted August 13, 2013 Author Share Posted August 13, 2013 Do you put it in terms of cookies/candies? I find my kids understand subtraction and addition amazingly well when applied to something they really care about. For instance, if she thinks the answer is 3, ask her if she really only has 3 candies left when you take 5 away. If she understands the concept, she's probably just missing you on semantics when you are telling her to just subtract the ones and then you are saying she is wrong when she doesn't include the tens in her answer. Just my take, of course. This! She usually gets the concept, but the wording trips her up! Today, we did the same exact lesson as yesterday, but I worded things differently and the lesson went MUCH BETTER. :) I sometimes forget about pulling out the candies for a math lesson, but it always works wonderfully! My PS K teacher MIL hates that she can't use candy anymore to show math concepts! Quote Link to comment Share on other sites More sharing options...
Mom2TheTeam Posted August 13, 2013 Share Posted August 13, 2013 My son is AWESOME with addition. He really struggles with subtraction. He just finished his 1B workbook today. (Big cheer! :hurray:) Subtraction was really a struggle. I feel like I probably didn't spent enough time solidifying it at the lower numbers, like within 20. We hand to stop on subtraction within 100 for quite a while. So, I would suggest hanging out until you are sure she really fully gets it before moving on. I know c-rods are awesome, but we don't use them much. So, I can't help there, but I'd just keep on working at even if it's in very similar ways over and over until you are sure she has it down well. Good luck! Quote Link to comment Share on other sites More sharing options...
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