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Wednesday, November 29, 2017

Fractional exponents


An exponent is the believer of some truth. One person; some perceived truth. In math, an exponent is the power to which a number should be raised. The old squares. Two times two times two is two to the third power, is two times two is four times two is eight. The truth is the third power, the exponent is two. Two believes its third power is eight.

It gets worse. Fractional exponents. Why isn’t the exponent a whole number? Who did this! We must understand the fraction to get the truth. There are rules. Find the least common denominator, for instance. But, enough! I don’t have to do this anymore. It’s Laura who must, and who does not understand.

She is so frustrated. She claims to have studied it in Google, on You-Tube, and, especially to have asked her math teacher. “But, he just knows it; he doesn’t teach it,” she groans. The school year is almost half over. I explained to her the math teacher’s job is to teach as well as know, and she must be student enough to say that to him. Today.

Don’t make me do this again, please. Don’t make me tease out all the little chunks that must be solved to find the exponent. Because the real truth is, I don’t know what the answer to all the chunks tells me, except all the rules were observed. This is far more algebra than I ever bargained for. Why would you have twenty five over nine, let alone want to raise it to the one half power.

I told Laura, if the teacher cannot teach you, your grandmother will know the reason why. I’ll see if that works.


Test: derive a fractional exponent from the example shown.


35 comments:

  1. Hari OM
    Can I offer a doctor's note to skip that test???

    Good grief. I managed through maths of the old fractional and logarithmic to adequate level and then left it alone. I don't envy Laura this one. Yeecchhh... YAM xx

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  2. Did she try Khan Academy on youtube? He is very good at teaching and its free.

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    1. I was going to suggest this, too.

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    2. As was I. Khan has saved Son Donald on many occasions.

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    3. Me too. Sal Khan explains it all very clearly. My granddaughter and I check with him regularly. There is so much I have forgotten.

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  3. We cats LAUGH in the face of fractional exponents. LAUGH!

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  4. My mother and my youngest brother fought over which of them did my maths and physics homework. I let them.

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  5. That example looks like Toby is pointing to the cat treats cupboard and demanding you open it. Math.....shiver.......I do well to manage the simple basic math of add/subtract/multiply/divide and yes please, pass the calculator. Laura is lucky to have you on her side.....teacher beware.

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  6. We never called them exponents at school. It was a number to the power of or something was squared or cubed. I would write the numbers out like, 2 to the power of 3, I would write out 2 x 2 x 2 and it equals 8. I guess Laura already knows this though. (I can't do superscript figures on my keyboard which might have illustrated better).

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    1. That's why I had so many chunks of answers because I had to convert it all to 2x2x2. I never found a use.

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  7. I'll give that test the old college try: Fridge to the power of (Toby divided by upper cupboard) ...?

    And the answer: da-da! suppertime in the Noragon household.

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  8. Which lunatic thought up that way of explaining something simple...

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  9. Joanne, go online to Khan Academy.

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  10. Whoah. My head is spinning. I am SO sympathetic to Laura.

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  11. I liked algebra I and geometry I, I made it through algebra II OK but geometry II was a trial. I still needed one more math credit and the next step was chemistry (yes, it was a math credit, involved a slide rule, and yes this was before calculators). the only reason I passed Chemistry is because my teacher took pity on me. I was a straight D student but not for want of trying. When I was the last student determined to take every single minute allowed me to take my exam, the teacher walked up to my desk and asked me if I would settle for a D. I could have kissed her. my response was a heartfelt relieved 'yes'. she didn't even grade it.

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  12. "he just knows, he doesn't teach it" is a problem with far too many teachers, even back when I was in school. kids like me passed exams by memorising, not by understanding the work. I well remember the year we had a math teacher who loved his subject and knew how to teach it. I had several "lightbulb" moments where I actually understood what we were learning and if I'd had teachers like that all through my school years I would have done much better. Instead I sat through most classes being bored and memorising just enough to pass.

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  13. Math was my worst subject in school and just thinking about this equation gives me a headache.

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  14. I love math and my mind used to figure out all kinds of complicated problems. That is not anymore and when that skill left me a year or so ago, I mourned. Now I don’t care, I just need to know how to make the equation and Excel will do it for me - or Siri, or Alexa or whoever will be the next voice that comes with some electronics.

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  15. I went to a community college. One of my computer classes was taught by a woman who we later discovered was taking the same class at a nearby university. By the way she failed. I had dropped the class because I did not understand what I was doing and she was not helping. Unfortunately you can't do that in high School.

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  16. Seems to me I struggled with this, along with son, when he was in high school. This is perhaps when you want to find a tutor?

    betty

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  17. I had a brilliant math's teacher and that was the problem he was brilliant at maths but could not teach. I failed.

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  18. my father used to teach maths...then he moved to a junior school where he taught children!
    His method worked at both ( and in the high school he worked with those who didn't want to attend). Make whatever you are teaching fun.In math play with the numbers, find unexpected patterns to understand what is going on. teachers are not allowed to do that now, they are told what and how to teach.....

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  19. Give Khan Academy a try (www.khanacademy.org). They are free to use and also have embedded videos to explain different algebraic concepts. They also give you lots of problems to practice on!

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  20. Did you say something, Joanne? I just heard blah blah Laura, blah blah algebra. I think I tuned out because algebra is traumatic. Steph is right, Khan academy is great. Also, if you have a book with the answers in the back, like I did, you can keep working the problem until you get to the right answer and then test your process on additional problems. Time consuming but that's how I got through algebra back in the day. I feel badly for you. And for Laura. Good luck!

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  21. And THAT's why I majored in English.

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  22. Fractionally, Toby is going to land on his feet.

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  23. The prose description makes my head spin. I think I would need to see it visually in math terms.

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  24. I haven't the faintest idea what you're talking about! What's wrong with the two times table? Or using one's fingers .

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  25. I do not understand why algebra is pushed down everyone's throat, have hardly ever used it and I've been a teacher. Once told my college algebra teacher that if finishing the book was the objective of the course he'd done it, but if the objective was to teach the class algebra he hadn't done it. He'll at that teacher, tell him to teach.

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  26. I am glad we are beyond all the math crap. It was very hard to get Harley through it with a passing grade. And by passing I mean a D. The teachers don't seem to be of much help now days!

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