Kfamily Posted September 23, 2008 Share Posted September 23, 2008 I would like to skip this lesson in R&S 6 but if it is important to know I will not. It seems like a lot of work for not much and they even warn that it will not be a reliable check of multiplying if errors are made with zero. Should we go ahead with this lesson or can I skip it? Thanks for any advice.:001_smile: I did search the board for any old information on this before posting but couldn't find anything. Quote Link to comment Share on other sites More sharing options...
Guest Dulcimeramy Posted September 23, 2008 Share Posted September 23, 2008 We went over this last week! I felt the same way. Taught it anyway; turned out to be the right decision. He "got it" better than I did and enjoyed the lesson. DH says it is good to know. I was prepared to drop it if the lesson didn't really take. I can't imagine using it, myself. Quote Link to comment Share on other sites More sharing options...
Anne Posted September 23, 2008 Share Posted September 23, 2008 My dds enjoyed learning this - they thought of it as a trick and they liked knowing a shortcut! I can't say that either of them use it now that they're out of their teens - My older dd might since she's teaching jr. high! I'd say teach it as a fun thing! Anne Quote Link to comment Share on other sites More sharing options...
yslek Posted September 23, 2008 Share Posted September 23, 2008 MUS has this as an appendix in one of their books (Gamma, I think), as an optional "extra". :) Kelsy Quote Link to comment Share on other sites More sharing options...
Alana in Canada Posted September 23, 2008 Share Posted September 23, 2008 What is it? If you don't mind my asking.:confused: Quote Link to comment Share on other sites More sharing options...
VaKim Posted September 23, 2008 Share Posted September 23, 2008 MUS has this as an appendix in one of their books (Gamma, I think), as an optional "extra". :) Kelsy Yep. I'm probably skipping it. Here is an explanation of what it is: http://en.wikipedia.org/wiki/Casting_out_nines Quote Link to comment Share on other sites More sharing options...
Camy-7 boybarians 1 lady Posted September 23, 2008 Share Posted September 23, 2008 We skipped this concept (3 of my boys so far). Blessings. Quote Link to comment Share on other sites More sharing options...
Lolly Posted September 23, 2008 Share Posted September 23, 2008 We cover it. It is a cool little trick to know. We go over the lesson. I have them use it in the next couple of lessons. After that, I leave it up to dc whether or not they use it. Most of the time, they decide against it. Ds seems to be fascinated with it however! Quote Link to comment Share on other sites More sharing options...
fivetails Posted September 23, 2008 Share Posted September 23, 2008 We just came across this last week - I'd never heard of it before. :001_huh: I read it, tried it..cool trick. Seems to take almost as long as actually *doing* the problem again though :tongue_smilie: ....I showed dd11 how it works and she just kinda said "eh..cool I guess." Good enough. ;) Quote Link to comment Share on other sites More sharing options...
Lizzie in Ma Posted September 23, 2008 Share Posted September 23, 2008 Seem to have done ok so far. :D Then again, perhaps my life has been unenriched and unfulfilled, holy cow, maybe I should go learn it!! What if I have needed it all these long years and never knew it?????????:eek: Quote Link to comment Share on other sites More sharing options...
claire up north Posted September 23, 2008 Share Posted September 23, 2008 I skipped it. No regrets. ;) Quote Link to comment Share on other sites More sharing options...
charlotteb Posted September 23, 2008 Share Posted September 23, 2008 We started the year using R&S 6th grade math for DS. I was looking over the book and saw the casting out nines lessons. I had never heard of it before and it really confused me. We did not continue using R&S because it wasn't a fit for DS. But if we had, I had planned to skip that lesson. Quote Link to comment Share on other sites More sharing options...
Heather in VA Posted September 23, 2008 Share Posted September 23, 2008 I'm a math major and never heard of it until I read about it a year or two ago on this board. So I figure if I could make it that far without knowing - it's not really crucial. Heather Quote Link to comment Share on other sites More sharing options...
Colleen in NS Posted September 23, 2008 Share Posted September 23, 2008 I would like to skip this lesson in R&S 6 but if it is important to know I will not. It seems like a lot of work for not much and they even warn that it will not be a reliable check of multiplying if errors are made with zero. Should we go ahead with this lesson or can I skip it? Thanks for any advice.:001_smile: I did search the board for any old information on this before posting but couldn't find anything. Well, I finally learned it a few weeks ago with R&S 6, too, and I am glad! It's faster than having to reverse factors and check an answer that way. It offers an alternative to going back over the problem to check (which, because you've already done the problem once, might cause you to go over it unthinkingly). I figure it doesn't hurt to have a 3rd option for checking answers. Sure, there is that margin for error, but if you are fairly accurate most of the time (you know your math facts, you know the processes well), it's a nice, shorter method for checking. As an aside, this skill does continue to be practiced in the review problems in R&S. Quote Link to comment Share on other sites More sharing options...
Julieofsardis Posted September 24, 2008 Share Posted September 24, 2008 It's not necessary, just a nice little extra trick. Quote Link to comment Share on other sites More sharing options...
Kfamily Posted September 24, 2008 Author Share Posted September 24, 2008 I think we'll skip this lesson. :001_smile: Quote Link to comment Share on other sites More sharing options...
2cents Posted September 24, 2008 Share Posted September 24, 2008 We skipped this. Haven't missed anything IMO. It is just an extra that I didn't think we needed to spend time on. Quote Link to comment Share on other sites More sharing options...
Jill in Maine Posted September 24, 2008 Share Posted September 24, 2008 When my daughter first learned this in Abeka I told her it seemed silly so I brushed over it...somehow I took a closer look and realized it was worth a try. This was several years ago and I don't think she has ever handed in a math test since without casting out 9's on any computation problems because this way she can be sure that at least those problems are correct...increasing her chances of a higher test score. I'm now working with my son on this. He is resistent, but he also hates loosing points on tests because of one digit off in an answer. He takes his first test tomorrow, and I bet he will find a few errors when I make him cast out nines before passing it in. It sure beats the other methods of checking....and once you get the hang of it it is MUCH faster! Hope this helps. Jill Quote Link to comment Share on other sites More sharing options...
Cindy in MO Posted September 25, 2008 Share Posted September 25, 2008 I made it through calc III without needing it, so I felt it wasn't worth our time. Cindy Quote Link to comment Share on other sites More sharing options...
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