tag:blogger.com,1999:blog-4242439961617529545.post5846303820443054858..comments2017-01-23T22:07:03.431+00:00Comments on Resourceaholic: Common Errors Made by Maths TeachersJoanne Morgannoreply@blogger.comBlogger48125tag:blogger.com,1999:blog-4242439961617529545.post-56740874060380069582017-01-08T18:02:16.251+00:002017-01-08T18:02:16.251+00:00How about saying that multiplication binds tighter...How about saying that multiplication binds tighter than addition/subtraction? An alternative would be that multiplication takes precedence over addition/subtraction.Angelos Sphyrishttp://knightofmathematics.weebly.comnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-4989854789687436302017-01-06T21:54:44.993+00:002017-01-06T21:54:44.993+00:003 - 3x6 + 2 should give us the same answer as -3x6...3 - 3x6 + 2 should give us the same answer as -3x6 + 2 + 3 or 3 + 2 - 3x6. The sign in front belongs to the number. <br /><br />That's how I think of it in my head although I've yet to find a good way of explaining it to the kids that need it. Moving the numbers around like that has tended to confuse them. 1violalasshttp://www.blogger.com/profile/10577884231709442969noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-60469396877062141902016-11-03T03:15:20.504+00:002016-11-03T03:15:20.504+00:00Yes, same here, noticed a lot of using incorrect v...Yes, same here, noticed a lot of using incorrect vocabulary expressions and equationsDoa Sholat Dhuhahttp://fazzams.comnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-49097735059435112842016-09-07T17:23:48.141+01:002016-09-07T17:23:48.141+01:00@1violalass You are absolutely right, although I a...@1violalass You are absolutely right, although I am quite sure that when I wrote the above it was in response to the issue of whether 0 was even or odd, not whether it was positive or negative. It is possible, however, that I may have misread the comment or perhaps confused it with a different comment (on whether 0 is even or odd), which appeared somewhere else. :)<br /><br />Anyhow, I apologise Angelos Sphyrishttp://knightofmathematics.weebly.comnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-46027593945409473332016-09-06T16:25:24.958+01:002016-09-06T16:25:24.958+01:00I agree that some of these things are not of conce...I agree that some of these things are not of concern to students but this was clearly a post for teachers, not students. 1violalasshttp://www.blogger.com/profile/10577884231709442969noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-14421201616747305012016-09-06T16:23:53.199+01:002016-09-06T16:23:53.199+01:00There may well be a good reason for zero to be eve...There may well be a good reason for zero to be even but that's not what the post above was talking about. 1violalasshttp://www.blogger.com/profile/10577884231709442969noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-7077951877622406752016-08-02T11:00:52.759+01:002016-08-02T11:00:52.759+01:00I taught my students both "nonagon" and ...I taught my students both "nonagon" and "enneagon" :-)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-20188719505983981252016-08-01T19:53:24.898+01:002016-08-01T19:53:24.898+01:00Thanks for all the fascinating comments on this po...Thanks for all the fascinating comments on this post - please keep them coming! Joanne Morganhttp://www.blogger.com/profile/11919801458664779971noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-24381106843879920452016-08-01T17:55:01.549+01:002016-08-01T17:55:01.549+01:00This has been a very informative article all round...This has been a very informative article all round and I would be happy to see it augmented, enhanced and become a reference for misconceptions. Apart from the comments I made elsewhere in reply to various people, I have a few more points:<br /><br />Square root<br />I normally write ±√a to indicate the solutions to x^2 = a for a >= 0. I feel that this serves to reinforce the fact that √a is Angelos Sphyrishttp://knightofmathematics.weebly.comnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-13738921914987441882016-08-01T17:50:09.606+01:002016-08-01T17:50:09.606+01:00There is a good reason why zero is even. The "...There is a good reason why zero is even. The "congruence modulo n" relation (where n is a positive integer) is defined as follows:<br /><br />The integer x is congruent modulo n to the integer y if and only if n divides the difference x - y. In this case, we write x ~ y mod n. Effectively, x and y have the same remainder upon division by n. <br /><br />This is an equivalence relation onAngelos Sphyrishttp://knightofmathematics.weebly.comnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-46563653253211685032016-07-15T00:07:29.864+01:002016-07-15T00:07:29.864+01:00No, I think the Romans added July and August when ...No, I think the Romans added July and August when they changed the calendar. Named after their Caesars.<br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-56144853480877364102016-06-30T10:36:44.521+01:002016-06-30T10:36:44.521+01:00I agree totally with Jo and Stephen here.I agree totally with Jo and Stephen here.Angelos Sphyrishttp://knightofmathematics.weebly.comnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-29537845367678678852016-06-30T10:33:01.910+01:002016-06-30T10:33:01.910+01:00About the last bit: I would interpret 4x^2 as 4 . ...About the last bit: I would interpret 4x^2 as 4 . x . x<br /><br />To get 4x . 4x, I would need to write (4x)^2<br /><br />Otherwise, I agree with what you say about pronouncing 4 cm^2. Angelos Sphyrishttp://knightofmathematics.weebly.comnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-57957897607728607652016-06-30T10:18:51.756+01:002016-06-30T10:18:51.756+01:00It is because the year used to start with March, n...It is because the year used to start with March, not January. Hence these months were 7th, 8th etc.Angelos Sphyrishttp://knightofmathematics.weebly.comnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-39011962036332268012016-06-28T13:23:33.145+01:002016-06-28T13:23:33.145+01:00I agree with most of what you say, but I would lik...I agree with most of what you say, but I would like to offer an ounce of help. You say that 'An "isosceles" triangle is a "same=sides" triangle in Greek'.<br /><br />Actually, this isn't correct. The "sceles" in "isosceles" comes from the Ancient Greek word "σκέλη" (= "scele"), meaning legs. See https://en.wiktionary.org/wikiAngelos Sphyrishttp://knightofmathematics.weebly.comnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-33203619803369386232016-06-27T23:13:26.698+01:002016-06-27T23:13:26.698+01:00Stephen,
That is how they got their name originall...Stephen,<br />That is how they got their name originally. Probably for your lifetime, they have been the 9th through 12th months.<br /><br />Kind of reminds me of the <a href="https://en.wikipedia.org/wiki/The_Hitchhiker%27s_Guide_to_the_Galaxy_(novel)" rel="nofollow">Hitchhiker's Guide to the Galaxy</a> trilogy--that has 5 books.Chad T. Lowerhttp://www.blogger.com/profile/05775614186613075069noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-10431139217391704872016-06-27T22:27:44.339+01:002016-06-27T22:27:44.339+01:00I think both are okay. 1 cm squared is 1 lot of a...I think both are okay. 1 cm squared is 1 lot of a unit of area measuring 1cm by 1 cm in the shape of a square i.e. (1cm)^2. "4 cm squrared" is 4 lots of a unit of area measuring 1cm by 1cm in the shape of a square. This could be seen more clearly if you pause after pronouncing the number i.e. 4 cm squared. I think people pronounce it square cm to avoid any potential confusionChris Howletthttp://www.blogger.com/profile/15387057299599068288noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-74984369893782068482016-06-27T08:31:48.066+01:002016-06-27T08:31:48.066+01:00Here is the problem with questions like 'is a ...Here is the problem with questions like 'is a cylinder a prism?' or 'is an equilateral triangle also an isoceles triangle?' It's that little word "is". <br /><br />Without going into detail here -- those who wish should Google 'Korzybski' -- let me suggest a strategy that should help enormously when you are faced with "Is x a y?" questions that donDoug1943http://www.blogger.com/profile/03833632801624062004noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-50079374979583802352016-04-19T11:23:55.975+01:002016-04-19T11:23:55.975+01:00I've seen a website where they'd spelled f...I've seen a website where they'd spelled frustum 'fustum'. <br /><br />Oh the irony, glass houses, all of that.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-22545462367433626252016-03-13T12:48:20.401+00:002016-03-13T12:48:20.401+00:00I agree Jo, and I don't think it is pedantic t...I agree Jo, and I don't think it is pedantic to want correct and precise mathematics or vocabulary. I'd wager no one accuses English teachers of pedantry ilwhen they correct students who have used the wrong "their" or "your" or "too"Stephen Cavadinohttp://www.blogger.com/profile/08497166692282461180noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-81149577623362458192016-03-13T12:42:09.446+00:002016-03-13T12:42:09.446+00:00Are you sure September, October, November and Dece...Are you sure September, October, November and December are the 7th, 8th, 9th & 10th months respectively? I always thought they were the 9th, 10th, 11th and 12th months....Stephen Cavadinohttp://www.blogger.com/profile/08497166692282461180noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-10167512758068728512016-03-03T09:02:38.100+00:002016-03-03T09:02:38.100+00:00Reading all of this is fantastic - we need to work...Reading all of this is fantastic - we need to work together and support each others' learning and delivery, especially with the political upheaval and changes ahead, we have a hard enough job as it is, so agreeing the best or better approaches to ensure students understand their work, as well as developing consistency is surely a good thing.<br />Thanks everyone.....<br />My own bug bear is Mrs LJhttp://www.blogger.com/profile/09907444876683553316noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-7076295730620337032016-03-03T08:30:34.657+00:002016-03-03T08:30:34.657+00:00When I teach it, I use heptagon, mostly because th...When I teach it, I use heptagon, mostly because that is what is located in the textbooks. However, I can see how students can get confused (or better yet-easily remember) the septagon version. After all, if you think about our calendar, it would parallel very well:<br /><br />december - 10th month; decagon - 10 sided<br />november - 9th month; nonagon - 9 sided<br />october - 8th month; octagon -Chad T. Lowerhttp://www.blogger.com/profile/05775614186613075069noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-17843042263906991972016-02-18T11:48:49.668+00:002016-02-18T11:48:49.668+00:00I've been thinking about this comment... I agr...I've been thinking about this comment... I agree that *some* of this stuff is a bit pedantic. But you can't deny that accuracy and precision of language is important in mathematics. <br /><br />There are some suggestions that I may choose to ignore - though others would protest. For example I say the number -5 as 'minus five' even though I have been told that I am wrong (I should Joanne Morganhttp://www.blogger.com/profile/11919801458664779971noreply@blogger.comtag:blogger.com,1999:blog-4242439961617529545.post-62224757836512070952016-02-17T17:48:15.459+00:002016-02-17T17:48:15.459+00:00Should be (Pi x diameter squared)/4
:)Should be (Pi x diameter squared)/4<br /><br />:)Anonymousnoreply@blogger.com