sleepymommy Posted October 19, 2011 Share Posted October 19, 2011 Ds7 has known his math facts for awhile now but I just want him to keep practicing because he tends to forget or get slower with them after some time. I picked up the book "2+2 is not 5" from B&N today because I remember reading some good reviews of it on here. It's a pretty straightforward book with lots of math 'tricks' in it. For example, for adding 9s it is called Magic 9s: 9+8 = 17 because 7 is one less than 8, then put a 1 in front. or 9+5= 14 because 4 is one less than 5, put a 1 in front. This is different from SM's 'make ten' method. Another example would be "Number in the Middle": 6+4 = 10 because 5 is the number b/w 6 and 4 and you double it. 3+5 = 8 b/c 4 is the number b/w 3 and 5 and double it. I think it's nice to have an arsenal of math tricks in you back pocket to help when you need it, but I also don't want to confuse him with too much and cause him to over think about simple addition. My question is do you think it would confuse him OR conflict with the way he has learned math via Singapore method? Quote Link to comment Share on other sites More sharing options...
Crimson Wife Posted October 19, 2011 Share Posted October 19, 2011 As long as he understands that the "magic 9's" trick works because the 1 in the digit stands for 10, I don't see the problem. It's just a shortcut, that's all. My younger brother still does the "fold down the finger" trick for remembering his x9's. Quote Link to comment Share on other sites More sharing options...
Farrar Posted October 19, 2011 Share Posted October 19, 2011 What am I not getting? It's phrased differently, but conceptually it is the same as the make ten idea that SM, MM and other programs I've seen teach. The number in the middle one is one I've not seen though. Quote Link to comment Share on other sites More sharing options...
monalisa Posted October 19, 2011 Share Posted October 19, 2011 I don't use Singapore, but I tried the book last year with my dd 8.5 to help her with math facts, and it did not help her at all. It became too many "tricks" to try to keep track of, and a full black and white page of math facts was just too much and would cause melt down. I like some of the tricks, personally, but it works better for me to just remind her to make 10 when adding 8 or 9, or doubles plus one, or monkey in the middle when adding numbers that are 2 apart, than to practice them over and over. Some of the tricks got a bit weird as I recall (like tall numbers or straight numbers or something). I am sure those tricks are helpful for some kids, but it just made math fact frustration worse for my dd (who gets math concepts easily, but has a hard time spitting out facts quickly). Quote Link to comment Share on other sites More sharing options...
letsplaymath Posted October 20, 2011 Share Posted October 20, 2011 Magic 9s: 9+8 = 17 because 7 is one less than 8, then put a 1 in front. or 9+5= 14 because 4 is one less than 5, put a 1 in front. "Number in the Middle": 6+4 = 10 because 5 is the number b/w 6 and 4 and you double it. 3+5 = 8 b/c 4 is the number b/w 3 and 5 and double it. I think it's nice to have an arsenal of math tricks in you back pocket to help when you need it, but I also don't want to confuse him with too much and cause him to over think about simple addition. If you teach these as "tricks" to memorize and apply, then you are adding a HUGE cognitive load and making math more difficult than it has to be. But if you take time to play with these tricks and see why they work -- like, the reason you use the "one less" number in the Magic 9s trick is because the 9 has taken 1 for itself, in order to become a 10 -- then you are deepening the student's understanding. I still might not want to do too many of the tricks, but I don't think they would be harmful. For instance, can your student see that "Number in the Middle" will work for ANY two numbers you want to add? If you want to add 10 + 20, that is the same as double 15. Or 40 + 60 is the same as double 50. All you are doing is taking the extra amount on the bigger number and sharing it between the two numbers. A lot of Singapore Math word problems will use a similar trick: "May had 70 stickers and her brother Joey had 40. She gave him some stickers, and then they both had the same amount. How many stickers did May give Joey?" Quote Link to comment Share on other sites More sharing options...
sleepymommy Posted October 20, 2011 Author Share Posted October 20, 2011 Thank you everyone for your thoughts! I think I'll continue with the book but I won't emphasize learning the tricks too much. I'll let him try to "see" how it works and then try to deepen the understanding to other larger numbers as suggested so he can understand why. If he takes to them then great! But if he doesn't, well then there are a ton of problems in the book, at least he'll have had a lot of extra practice. Thanks again!!! Quote Link to comment Share on other sites More sharing options...
Iucounu Posted October 21, 2011 Share Posted October 21, 2011 My question is do you think it would confuse him OR conflict with the way he has learned math via Singapore method? The add-nine rule you gave certainly runs that risk. I'd give it a miss; it sounds focused on rules without understanding. Quote Link to comment Share on other sites More sharing options...
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