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Math (subtraction) problem-advice?


shan.non
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My daughter is 8 and math comes easily to her. She doesn't really enjoy it and will just rush to get it done. Normally this isn't an issue but lately when I give her a set of subtraction with borrowing involved she will get all of them incorrect. What she is doing is, for example, 50-27 she will subtract 7-0 instead of 0-7 and borrowing. Her answer will be 37. If I point to the problem and ask her what is incorrect she can do the problem correctly. Then she can go do a whole set correctly. Is this something that I should worry about or is she just rushing? My gut says to keep doing this sort of problem daily until she quits manipulating the problem to make it the easiest but I want to make sure I am overlooking something. My other thought is to reteach it to her another method. We learned using Righstart on the abacus. She can do it correctly on the abacus no problem. Thanks for any advice!

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I would assume they are careless mistakes due to rushing at this point. I would just tell her to stop after each question for you to check her working and answers for the first few questions to make sure they are done correctly. Then let her continue doing the rest of the set.

If she is copying the question wrongly you would be able to notice right away. Then you would have to see if it is carelessness or a vision issue.

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My ds will still occasionally do that with a subtraction that has the 0 on top. It's a careless mistake. It's so easy to just glance at a problem like that and think 7-0 is still 7. When I notice my ds doing this I ask him to look at it again. I think it's normal for a child to have these little mistakes. He'll still do 4x4 is 8 because he glances at it and thinks two 4's. Oddly enough he doesn't do that with other double numbers. 2x2 or 5x5 etc. The 4 is his ingrained careless mistake. 

 

He had these careless mistakes a lot more often when he was younger. I think as long as you're sure she understands the concept, it's likely just a mistake. Just keep pointing them out and having her correct them and she'll mature enough to be aware of them on her own. 

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Thank you, good to be reassured it isn't a learning issue and I will just keep plugging along :) I plan to have her do two or three on the whiteboard each day, even if they are not part of the lesson until she becomes less careless. Thanks again :)

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I make my DD read the problems to me aloud before she starts and this seems to prevent these issues - I think because the auditory must go with the visual. But then I also sit with her and make sure she knows to start with the ones column and then read that to me correctly too before beginning - at some point I will let her loose, but I need to know she can do the steps with manipulatives and written and explain it to me before being set loose to do it on her own. 

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My husband thinks I need to let her fail a test and she will try harder the next time. He remembers comparing grades in private school and if you got an A you got two stars and Bs got you one star. They had contests boys against girls with winners getting a pizza party or something. I told him that is certainly motivating for kids who gets high grades but how awful for struggling kids who let down their team. I feel that if I hand her a test without going over the instructions she would not read the instructions herself and just do what she wants. I need to work on pointing out the instructions so that she begins paying more attention.

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IMHO it would not be a good idea to practice doing the problems wrong whether on a problem set or a test.  Even if just careless error, she is practicing that and cementing it in her mind to do it the wrong way.

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My husband thinks I need to let her fail a test and she will try harder the next time. He remembers comparing grades in private school and if you got an A you got two stars and Bs got you one star. They had contests boys against girls with winners getting a pizza party or something. I told him that is certainly motivating for kids who gets high grades but how awful for struggling kids who let down their team. I feel that if I hand her a test without going over the instructions she would not read the instructions herself and just do what she wants. I need to work on pointing out the instructions so that she begins paying more attention.

 

 

It's personal preference, but I don't feel that an 8 year old necessarily needs to have tests and grades, and especially not rewards fro the grades, which are supposed to be the reward themselves. Reward a reward?

 

In a homeschool environment  it's much better to keep practicing and working alongside a young child. 

 

For learning maths sake. If you start going too far down the grades and rewards (pizzas or stickers) path, you may find that the reward becomes the goal, when learning math and the pride of a job well done and effort out forth ought to be the reward.

 

 

I agree with Pen, correct it as soon as you see it. With plenty of practice it will get better. You're sure she understands the concepts, that's the important part.

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I'm not sure how helpful this will be so take it for what it's worth.  I gave my DD's  the language to walk through the steps by themselves.  Once they had the language mastered, they mastered subtraction.  Example:  When looking at a problem like 50-27...." I start with the ones columns.  Can I take 7 from zero?  Nope, because 7 is bigger.  I have to borrow."  Until they mastered the language, I had them correct their own work by adding.  They caught on pretty quick.

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I used manipulatives as well to help with this concept.

 

C-rods especially.

 

So we would put down 5 ten rods to make 50. Make note that we have no white 1 rods. We want to take 7 but we can't because we have none. We take a ten rod and change it into 10 white 1 rods. Now we can take 7 away and take 2 tens from our remaining ten rods. 

 

Even after a child understands this concept and can do it on paper and mentally, it might help to have them work through it visually with the rods at times if mistakes are common. 

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She gets it correct one hundred percent of the time while using a Rightstart abacus. She pretends to not know answers very frequently (or pretends not to see something) so it is quite frustrating. I don't want to do a reward system except one based on behavior-like if she does math with no complaining she can play a video game.

She did it again today and she got the answer wrong and I had her do it on the abacus (flipped vertically so you have to manually borrow) and she got it correct. I suppose I will make her use the abacus for awhile and do daily problems and maybe after a month I can try one without the abacus and see what happens.

Thanks everyone, it is great to hear other hs mom opinions.

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