Math Teachers Chatboard

rounding and approximation

by Math Teach to yikes

Nov 28, 2015

Yikes, your answer was spot on (I too was a math major).

Which leads me to ask:

Why is it that a High School Chemistry teacher can comfortably teach General chemistry to students, a High School Bio teacher can teach AP Bio to students, but when it comes to helping a kid out in AP Calculus, many math teachers run away?

Let...See More

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Many math teachers On 11/28/15, Math Teach to yikes wrote: > Yikes, your answer was spot on (I too was a math major).

Although I am a pretty self-confident guy, I appreciate the affirmation. > Which leads me to ask: > > Why is it that a High School Chemistry teacher can > comfortably teach General chemistry to students, a High > School Bio ...See MoreOn 11/28/15, Math Teach to yikes wrote: > Yikes, your answer was spot on (I too was a math major).

Although I am a pretty self-confident guy, I appreciate the affirmation. > Which leads me to ask: > > Why is it that a High School Chemistry teacher can > comfortably teach General chemistry to students, a High > School Bio teacher can teach AP Bio to students, but when it > comes to helping a kid out in AP Calculus, many math > teachers run away? > > Let's face it: As math majors, we took two semesters of > Calculus in our Freshman year in college, and Calculus III > and Diffy-Qs (typically) in our second year. This is clearly > analogous to what Bio and Chemistry teachers do during their > earlycollege training. > > So, Calculus is FIRST YEAR college material. So why the > aversion ????

weren't math majors? Heck by the time I was in college, having taken BC calculus in HS, I was taking Calc 3 and Linear Algebra in my first freshman semester. But then I come across math teachers who are seemingly clueless about math. Or even worse, administrators who are clueless about math who were math when they taught.

Like the former math teacher AP who didn't understand what a ring was when I told him that I used ring and field theory concepts to explain to my kids order of operations. It wasn't that he didn't see how those concepts could be used to teach O of O, he didn't know what a ring or a field were, or even seem to recognize the terms.

Personally I love calculus and love to help kids with it even now that I'm retired (from teaching 7th and 8th grade - so I wasn't exactly refreshing my calculus memory there). I used to go to a coffee shop after school every day and would sometimes help students who attended the local community college with their math when they asked. I even had a former student (I had her in 8th grade) come back and ask for help years later when she was in college taking calculus. And now I go to our local senior center and there are some college students who work there part-- time and I suspect I will be helping some of them, as well. I look at it as if I have retired from teaching but not educating.

Are you familiar at all with the work of Dr. Wu, at Berkeley? He is a math professor with a great deal of interest in math teacher preparation, and while his emphasis is on the early years (where I think we would both agree we are woefully weak) he has a very clear, correct- mathematics orientation and I got a lot of benefit reading through some of his stuff - even the elementary stuff, as he is so clear and focused.

If you're interested in checking him out, this is the address. math.berkeley.edu/~wu/

Nov 28, 2015

rounding and approximation

by karen

Nov 17, 2015

I found difficulty in explaining the answer of this question to the pupil write the smallest and largest numbers that will give the following: 8460000 when rounded to the nearest ten thousand would please help

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Terri Go to dr math and search for rounding

[link removed]

On 11/17/15, karen wrote:

> I found difficulty in explaining the answer of this > question to the pupil > write the smallest and largest numbers that will give the > following: > 8460000 when rounded to the nearest ten thousand > would please help

Nov 17, 2015

Yikes On 11/17/15, karen wrote: > I found difficulty in explaining the answer of this > question to the pupil > write the smallest and largest numbers that will give the > following: > 8460000 when rounded to the nearest ten thousand > would please help

what a useless exercise. First of all it is horribly worded. I was a math m...See MoreOn 11/17/15, karen wrote: > I found difficulty in explaining the answer of this > question to the pupil > write the smallest and largest numbers that will give the > following: > 8460000 when rounded to the nearest ten thousand > would please help

what a useless exercise. First of all it is horribly worded. I was a math major in college and have worked in a math field in business for 20 years and taught math for 15 years and I had to read it twice to see what they were after.

Secondly, it is mathematically incoherent, as there is no greatest number that rounds to that nor is there a smallest number that rounds to that There is a largest and smallest WHOLE number that rounds to that, but without making that restriction, which the problem doesn't, it is a problem without an answer. Except, you are going to frustrate the dickens out of the brightest kids who assume that if you ask for an answer there is one, but who are smart enough to see this problem does not have an answer.

Try a simpler version - what is the biggest number that, rounded to the nearest 10, yields 100. well, 105 rounds to 110, so that is too big. 104.9 would work - but 104.9 is bigger and still rounds to 100. But 104.99 is even bigger and still rounds to 100. In fact, any number you can give me that rounds to 100 can be made bigger, while still rounding to 100 - just add another decimal place and put a 9 in it.

It is like asking "what is the biggest number that is less than 5". There is no answer.

Now lets say that you add the restriction and ask for the largest and smallest WHOLE numbers (proper wording is why it is important that math amateurs not make up test). Then you have a problem that at least has an answer questions, but is still of very questionable mathematical or pedagogical value.

So if a kid says there isn't any answer and can come up with any kind of semblance of an explanation indicating that they knows why I would be giving them full credit, an attaboy/girl, and marking them as someone to watch and expect great thing from. Unfortunately, in most classrooms I think they get marked wrong because it isn't the answer in the book. Which is why we need teachers, not just books and computers.

BUT - only if the teachers really know what they are doing. Which isn't always the case in math.

Nov 17, 2015

math BEDMASS

by HI

Oct 26, 2015

can u show me all the steps for this bedmas question: 2 raised to the power of 2[24 divided by 4(12 divided by 3)]

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harpazo On 10/28/15, harpazo wrote: > On 10/26/15, HI wrote: >> can u show me all the steps for this bedmas > question: 2 raised >> to the power of 2[24 divided by 4(12 > divided by 3)] > > 2[24/4(12/3)] > > 2[24/4(4)] > > 2[24/16] > > [24/8] = 3 > > Answer: 3

Note: The word is PEMDAS.

Oct 28, 2015

Please don't On 10/28/15, harpazo wrote:

> Note: The word is PEMDAS.

promote that nonsense. It is a terrible way to "remember" the order of operations, because too many students fail to remember the left to right rule because it is not embodied within the acronym. A memory "aid" that leaves out a critical thing that mus...See More

Oct 29, 2015

math

by Tanveer Ahmed

May 25, 2015

Hello Sir, I have a question .

A bird collector wants to buy 100 birds and to spend exactly $100. 1 Blue Bird= 7 dollars 1 Green Bird= 5 dollars 20 Yellow Birds= 1 dollar

How many blue, green, and yellow birds can he buy?

Please sir i'm waiting for your response. My email address is: tanveer-[email removed]

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I should have added On 5/26/15, Some direction wrote: > On 5/25/15, Tanveer Ahmed wrote: >> Hello Sir, >> I have a question . >> >> A bird collector wants to buy 100 birds and to spend >> exactly $100. >> 1 Blue Bird= 7 dollars >> 1 Green Bird= 5 dollars >> 20 Yellow Birds= 1 dollar >> >> How many blue, gr...See More

May 27, 2015

harpazo On 5/25/15, Tanveer Ahmed wrote: > Hello Sir, > I have a question . > > A bird collector wants to buy 100 birds and to spend > exactly $100. > 1 Blue Bird= 7 dollars > 1 Green Bird= 5 dollars > 20 Yellow Birds= 1 dollar > > How many blue, green, and yellow birds can he buy? > > Please sir i'm waiting for your res...See More

Oct 28, 2015

8th grade math

by shawn

May 19, 2015

i have not been to 8th grade but i am going on to highschool ive missed a year of education please help me with math

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coyoteboy Go to [link removed]!

May 22, 2015

harpazo On 5/19/15, shawn wrote: > i have not been to 8th grade but i am going on to > highschool ive missed a year of education please help me > with math

Go to mathtv.com for free math video lessons.

Oct 28, 2015

Pre-Algebra

by Richelle

Jun 2, 2015

5x<8x+27

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harpazo On 6/03/15, It is called an inequality wrote: > On 6/02/15, Richelle wrote: >> 5x<8x+27 > > Any other questions?

5x<8x+27

5x - 8x < 27

-3x < 27

x > 27/-3

Answer: x > -9

Oct 28, 2015

harpazo On 6/02/15, Richelle wrote: > 5x<8x+27

I have already answered this question.

The answer is x > -9

Oct 28, 2015

HS Geometry common core sequence

by ari

Aug 25, 2015

I've been searching for a reliable HS Geometry curriculum map to transition to from our current sequence. All I find on-line are references to EngageNY, which I don't really care for; they start off with constructions, which makes no sense to me. Does anyone have a Common Core Geo sequence and curriculum map that they used last year with positive r...See More

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Richard Schiller On 8/25/15, ari wrote: > I've been searching for a reliable HS Geometry > curriculum map to transition to from our current > sequence. All I find on-line are references to > EngageNY, which I don't really care for; they start off > with constructions, which makes no sense to me. > Does anyone have a Common Core Geo sequence > a...See More

Sep 1, 2015

harpazo On 9/01/15, Richard Schiller wrote: > On 8/25/15, ari wrote: >> I've been searching for a reliable HS Geometry >> curriculum map to transition to from our current >> sequence. All I find on-line are references to >> EngageNY, which I don't really care for; they start off >> with constructions, which makes no sense t...See More

Oct 28, 2015

calculus

by Gmoneymilkmayne

Sep 15, 2015

how do I find the cos of a fraction that is not on the unit circle

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harpazo On 9/15/15, Gmoneymilkmayne wrote: > how do I find the cos of a fraction that is not on the unit > circle

Post a specific math question.

Do you mean something like cos(1/9)?

Oct 28, 2015

Needs assessment of elementary math educators

by J.J. De Simone

Sep 22, 2015

Hi, fellow math educators. I'm currently working on a needs assessment project of elementary math teachers from which I create a professional learning program. My team partner and I are doing this for a class assignment in the Ph.D. program in Curriculum and Instruction at the University of Kansas. If you have 10 minutes to spare, we'd really appre...See More

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Tiffany how do you divide the number my math teacher said you multiply the lower number and subtract the others its hard can you tell me what it is so I could do it right.

Sep 22, 2015

harpazo On 9/22/15, Tiffany wrote: > > how do you divide the number my math teacher said you > multiply the lower number and subtract the others its hard > can you tell me what it is so I could do it right. >

Post your question. I need a specific question.

Oct 28, 2015