How pitiful is that?? LOL Dd brought home a work sheet for Math this weekend and it had something new on it. She did not have her book, so we couldn't go over that.

This is an example of the 3 problems that were part of this sheet. I don't know how to do all the symbols, so bear with me:

n to the 2nd power equals 196
n to the 3rd power equals 512
n to the 4th power equals 1296

In all of these, she needed to figure out the value of n.

I did figure out all the answers by trial and error AND using the calculator. However, they are not allowed to use them in class and I am sure the is some kind of equation, but neither dh nor I could remember it or come up with it. She of course, didn't remember either. So we need to go over this with her tonight again. Does anyone remember how to figure these out?

By Kiki on Monday, March 27, 2006 - 08:34 am:

There is a great website a friend of mine told me about it's called ask dr. math. Check for it online. It's a really good resource. I hope it helps.

By Dawnk777 on Monday, March 27, 2006 - 08:50 am:

Ask Dr. Math

Math.Com

By Insaneusmcwife on Monday, March 27, 2006 - 09:13 am:

ugh! I thought 3rd grade math was getting hard. Good luck!

By Kaye on Monday, March 27, 2006 - 09:49 am:

I don't know the formula per say. But for the double power one, we had to memorize up to 15 what they were.

Good luck!

I almost think it is trial and error, plus some memorization!

By Vicki on Monday, March 27, 2006 - 10:39 am:

I am not having much luck on those sites. It can't be trial and error can it?? My lord, it would take a 11 year old with no calculator forever to figure it out!! Took me long enough to do it with one!!

By Yjja123 on Monday, March 27, 2006 - 10:50 am:

Go to this website for explanation:

http://home.att.net/~numericana/answer/algebra.htm

By Vicki on Monday, March 27, 2006 - 10:59 am:

huh??? Good lord, I don't understand much of anything that site has to say. LOL Oh my, time to hire a tutor I think. LOL This is going to drive me crazy.....

By Ginny~moderator on Monday, March 27, 2006 - 11:21 am:

Yes, it's trial and error, but, as Kaye says, one needs to do a certain amount of memorization.

14 x 14 (14 squared or to the second power) is 196. I started with I know 12 squared (to the second power) is 144, and did trial and error on 13 and 14.

For the second one, again, it's trial and error. You know n has to be less than 9, because 9 to the second power is 91, and if you multiply that by 9 (to the third power) it would be a lot more than 512. So I tried working backwards, and
8 x 8 (2nd power) = 64 x 8 (3rd power) = 512

For the third one, you already know it has to be less than 8, because 512 x 8 (4th power) would be a lot more than 1296. So, try 7, and then 6. It turns out the answer is 6
6x6 = 36 x 6 = 216 x 6 = 1296.

There are some things in math where you just have to memorize some basic information, like the times tables up to 12, at least.

If she memorizes the times tables up to 12 (which I think should be a given by 5th grade math, but maybe not in "New Math"), then she can cut and try with pencil and paper. It takes longer, that's for sure, but if she has the tables memorized and does the comparison with earlier problems (as I did above), she should be able to manage.

By Ginny~moderator on Monday, March 27, 2006 - 11:25 am:

I have a son who is a math genius, and I will ask him if there is a formula, but I don't think there is. I know he has memorized the exponents of every number up to 100 to the third power, but he has a freaky memory, and I don't think it's necessary.

By Mrsheidi on Monday, March 27, 2006 - 01:07 pm:

Vicki, I'm in the middle of doing my taxes right now, but email me and I'll see what I can do.
Generally, they should be able to use calculators for these. You could also put it in another form like, 196 to the power of 1/2 and it will give you your answer. (512 to the power of 1/3, and 1296 to the power of 1/4.) Use the parentheses before you plug in your powers if you have a simple calculator. Like I said, I always use a calculator...it's just mean if they make them do it by hand.

email me; heidi henkel at hotmail dot com

ps- i'm surprised they are doing this in the 5th grade. the kids i tutor aren't doing this until at least the 9th grade. don't tell your daughter that though. it just discourages them.

By Vicki on Monday, March 27, 2006 - 01:57 pm:

LOL Heidi! I must have a simple calculator or else it is a simple operator because I just started multiplying numbers until I got to the right one. LOL This is the first paper that these came home on that she has to figure out what the "n" was. She has been doing the basic figuring out what 4 to the 6th power etc for about a week now. I just hate when they bring papers home with no directions on HOW to do the problems. I am sure they went over it in class, but she brings nothing home with examples or anything like that. Usually she does just fine and remembers how they were taught to do it etc. But when something does stump her, it would really help me to be able to help her with examples! One reason, I might know how to get the answer, but it might not be the way they want them to do it. So much has changed since I was in 5th grade!! Another reason, like this one, I just don't know!!! Holy cow, 9th grade!! What the heck is she even doing these for then!! That is a HUGE difference!!

By Mrsheidi on Monday, March 27, 2006 - 02:39 pm:

Is there a book that correlates to the worksheet?

By Dawnk777 on Monday, March 27, 2006 - 05:22 pm:

I thought 9 X 9 = 81, not 91.

So, the answer to the second one is 8.

-----------------

14 x 14 = 196

------------------

8x8 = 64
64x8 = 512

------------------

6x6 = 36
36x6 = 216
216x6 = 1296

----------------

It would be easy enough to do without a calculator. I just looked at the last number and tried to guess what number multiplied, would get that number.

By Ginny~moderator on Monday, March 27, 2006 - 06:15 pm:

Yep, you're right. That's what happens when I don't pay attention to what my fingers type.

By Vicki on Monday, March 27, 2006 - 07:21 pm:

She did not bring home a book Friday. It was just a worksheet that those 3 problems were included on. I figured out all the answers, but with them not being allowed to use a calculator, it would take her quite a while to do it by trial and error. I figured it out on the calculator by trial and error, but I figured there had to be some kind of formula for figuring them out. I just find it very hard to believe that 11 year olds are supposed to do it by trial and error and not be allowed to use a calculator, but I guess that must be the case!!

By Mrsheidi on Monday, March 27, 2006 - 09:00 pm:

1296 to the power of 1/4th
could also be described as this:
1296 to the power of 1/2 to the power of 1/2
1296^1/2^1/2 (since 1/2 times 1/2 equals 1/4)

And ANYTHING to the 1/2 power really just means that you take the square root of it.

So, for example, 81^1/2 equals 9 because it means you take the square root of 81.

Sooo... start with this sequence to get the answer:

n^4=1296

n=1296^1/4 (1296 to the power of one-fourth)

n=(1296^1/2)^1/2 (1296 to the 1/2 power, to the 1/2 power since 1/2 times 1/2 equals 1/4th)

So, anything to the 1/2 power means you take the square root so...
Square root of 1296 is 36 (she would have to figure this out by paper?) and then she would figure out the square root of 36, which is 6.

Your answer would be 6...and, this teacher needs a life.

By Kate on Monday, March 27, 2006 - 10:24 pm:

I still so don't get math....I think this proves I never will.

By Colette on Monday, March 27, 2006 - 10:26 pm:

http://nlvm.usu.edu/en/nav/vlibrary.html

I don't do math well at all. This is a site on our school website for math help.

By Colette on Monday, March 27, 2006 - 10:27 pm:

what does ^ mean?

By Vicki on Monday, March 27, 2006 - 11:01 pm:

To the power of

By Vicki on Monday, March 27, 2006 - 11:05 pm:

I understand that 2 would be the square root and the way that you describe it makes sense to me (I can't believe it LOL) on how you can figure out the 4th power!! Now, do you have a tip or trick for the 3rd power?

If you can believe it, tonights homework had nothing to do with any of it. It was on metric measurments!! We seem to be jumping all over the place the past few weeks!! Maybe we are done with it and I can forget about it for now. LOL

By Mrsheidi on Monday, March 27, 2006 - 11:21 pm:

Is she taking state tests during the day and the teacher is sending home busy work? Ugh. That's what my senses are telling me. It doesn't sound like this is the type of teacher who actually looks at what HW she's giving or grades it either.
At least you are a parent who is trying to keep up with her homework!!

And, nope, sorry no trick about the 3rd power. Like I said, I'm in shock that this teacher gave that kind of HW to a 5th grader. And, on top of it, they expect to do the work BY HAND? Is she supposed to take Trigonometry next year or something? LOL! Even the 12th graders I taught would have had to use their calculators! (Again, don't tell your DD this...it will only discourage her.)
But, I would send a note to the teacher privately, if possible. Do you have the teacher's email? I would just ask nicely...
"Dear Ms. Blah blah
I was concerned when we received homework the other night (give the specific HW questions and date it was given). Are fractional exponents part of the 5th grade curriculum?"

By Dawnk777 on Monday, March 27, 2006 - 11:43 pm:

One time Emily had pages in a workbook, of long division problems. she had a lot of trouble with it and it took her forever. Then the teacher never went over it in class. The next time, she brought her math workbook home, we went over those problems again. The second time through it, she understood it sooo much better and it went much more quickly. She was in 4th grade, then.

By Vicki on Tuesday, March 28, 2006 - 07:33 am:

No, the state tests were a few weeks ago. Thanks so much for the help Heidi. She did collect the homework, so I assume she is even grading it!! Sometimes she collects/grades homework, sometimes not... I am soooo ready for Spring break...LOL

By Kaye on Tuesday, March 28, 2006 - 08:10 am:

I will say that last year my dd had the same homework (as a 5th grader). She was allowed to use her calculator and it was more a matter of memorizing a list of squares. It was meant as an introductory to the concept.