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Sunday, November 01, 2015

Why '5+5+5=15' is wrong under the Common Core

Here's a "repeated addition" Common Core problem that's taught in third grade in US schools:

Use the repeated-addition strategy to solve: 5x3

If you answer the question with "5+5+5=15,” you would be wrong.

The correct answer is "3+3+3+3+3.”

Mathematically, both are correct. But under Common Core, you're supposed to read "5x3" as "five groups of three." So "three groups of five" is wrong.

According to Common Core defenders, this method will be useful when students do more advanced math. This way of reading things, for instance, can be used when students learn matrices in multivariable calculus in high school.

But parents aren't happy about it.

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15 comments:

  1. Common core is the socialist way of making math so complicated - just to make it so even the lesser capable students are equal to the more capable.

    Stifling the problem solving processes in favor of a standard solution is what got us in to the bottom of the educational capabilities list over the last couple of decades.

    How about we ditch common-core, teacher's unions, and appointed school boards and allow the students that can excel...the ones that can't will get to clean our streets and toilets - while continuing to vote Democrat!

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  2. Larty hpgan get rid of this Dosaster..

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  3. No wonder our children are struggling. This is the most ridiculous thing I've ever heard. They may want to consider teaching children the way their parents were taught. Maybe they would have more effective home support that way. SMH!

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  4. If the kids don't understand they can go ax their fathers.

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  5. Multivariable calculus in High School?? Where is this venerable school located??

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  6. If you get it right you get a lesser grade because someone who didn't get it right but tried really, really, hard .

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  7. More reason to take your child out of public school and put them in a private school, or home school them if you can!

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  8. But it's 5- three times.

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  9. common core is NOT common sense. kill common core now before it destroys more minds.

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  10. 3➕ 3➕ 3➕ 3➕ 3 is the correct interpretation.That is not an idea from common core It is just correct if you understand math. You can't dumb down math or in this case call it dumb because you don't understand you dummies.

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    Replies
    1. And I suck at math

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    2. And English apparently by starting a sentence with and

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    3. Yes I had a whiskey or too but I'm not driving. Mind your business. God bless Merica!

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  11. It's this kind of uber-rigid thinking that stifles kids.

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  12. I suppose that 4:43, being so vastly superior to the masses, didn't learn one of the most basic math properties, which most of us "dummies" learned in the 6TH grade --- the Commutative property, which states that two numbers can be multiplied in either order.
    Did Common Core so impress him that he forgot some of his math education? Does Common Core still TEACH math or is it more of an attempt to confuse and confound students? KISS, baby --- keep it simple. Common Core is so far off the mark on THAT concept, it can only be kept alive by people like 4:43.
    The solution to ANY math problem (as taught by REAL math teachers) is the simplest and quickest, not by taking a simple problem and turning a 2 step solution into a convoluted 8 step "solution".
    I can't wait to see how Common Core tells them to solve a quadratic equation -- their "solution" would probably take several hours (instead of a few minutes, and take 4-5 pages, instead of 1.
    Who's the dummy?????

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