I've been playing around with some dice rolling apps and tried this one. I had to laugh at the results. Anyone see an issue?

Yiiiikes.

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Looks to me like that dice rolling app is using Common Core Math principles. I see no issue; if it is good enough for public schools, it is good enough for hobby gaming.

That's an understatement. Some of the stuff from those books, especially the math, is really messed up.

True story: my 13 year daughter went from A to F in 7th grade accellerated math back in March. I asked her what happened. She told me that all the stuff I taught her in third grade finally ran out, and she didn't realize she needed to start paying attention in class.

You can use this, just save the html page to a flash drive or hard drive.

Common Core Math uses problems such as "Explain how 8 + 5 = 10" with the answer being "use only 2 out of the 5 so it equals 10"

We are not making this up.

Here's an example of a Common Core math problem and how they suggest solving it:

Oh, I see now !
I think it strange to teach that... But if that can help mental calculation, why not...

I am actually a mathematics *Major* and I think the only way this isn't going to confuse the heck out of the kids is if we are simultaneously also teaching collateral parallel brain processing...

That seems like a triumph of theory over application. Did they do any testing of that on real kids before they rolled it out? (Forget external threats, it looks like the USA is most in danger from its own internal bureaucrats!)

To me, once you understand what they're saying (basically, get one number to the closest 10, then you can just add the rest together easy as you please), it really does make some sense. However, the way they explain it makes it rather more confusing than what we had before - and if you miss out on some of the steps in between, you're going to come up with some wildly different results. And, since you're taking 4 steps per digit after the first (determine if the digits added together are greater than 10, add to the one until it hits 10, subtract the same from the second, then add the two together), rather than the one per digit we've had up to now (add the lowest digits together, if that's greater than 10, add one to the next digits up), there's a lot more room to be confused.

Yeah, it's great if you want to get kids thinking about the math more, and once they have it down pat, I imagine it's not really going to be any slower or worse than what we grew up with - but I do pity the teachers who have to teach it to kids (5+8=13 is a lot easier to teach and learn than 5+8=(5-2)+(8+2)=3+10=13, even if the last step is a lot more intuitive - and going up from there just makes things more complicated = 2+ extra steps for each extra digit!).

To be honest, this is actually the way that I tend to add, subtract and multiply. I've always been that way. When I have to multiply 42 by 28, for example, I usually would multiply 42 by 30 in my head first, then multiply 2 by 42, and subtract that from the first number.

But I know that the way my mind works isn't like most people, so I don't see this exactly working as a foundation for basic math for most kids. That's the part that confuses me.

Ninevah, I use similar tricks.
And as to the basic concept - whatever happened to just memorizing the tables? and let understanding seep its way in afterwards?

The intent is that the "why" is more important than the "what."

My third grader came home with the following problem:

How does knowing 15 + 3 = 18 help you solve 27 + 18?


That's it, no explanation or anything.

My wife looked at it for a while then turned to me and said, well I guess you have to help with math from now on as this makes no sense.

When someone with a college education can no longer help with a third grade math problem... We are in trouble.

What age corresponds to a third grader ?

Yeah, that does take a bit of thinking differently (for us of the old generation) - 18=15+3, and 27+3=30, which means 18+27=15+30=45 - which means that they're trying to get the idea across. But, and this is a pretty big but, unless they do so in such a way that the parents can understand the system, it's just going to come down to the teachers to make sure that the kids get it - and in a setting where (even in the best of circumstances) one teacher is responsible for 10+ students, and only have the students for an hour per day in order to get through a rather sizable curriculum, there simply isn't enough time for the teachers to give the students the individual attention they may need in order to get it (as has been mentioned several times - this is rather more complex to teach than just memorizing tables and then teaching how it works later).

Now that I see it and am getting an understanding of it... I'm not sure it's as bad as everyone has been making it out to be. It's different, certainly, and it takes a fair bit of thinking to understand the idea behind it - but it gives a better understanding of how the basics of math works and why the tables are the way they are. It makes the low end harder to learn - but it may help make learning the more difficult maths easier. But, at this point, it is far too early to tell.

[Edit] Though, honestly, in order to get the point across, I'd have worded it as, "How does knowing that 18-3=15 help solve 18+27?" That way, you have at least a bit of the process in the question itself, rather than relying on the kid just learning this stuff to infer that 15+3=18 is the same thing as saying 18-3=15 - and it would certainly give the parent something to clue into to say, "OK, they want me to subtract 3 from 18, so where does that 3 end up going?"

1) 8 - 9 years old is 3rd grade - my sons were born in October so they're on the older end of the spectrum.

2) my kids' classroom sizes are riughly 25-1 or worse, though there's often an aide who floats to help out. It's a challenge on the teachers who I do believe are trying their best. Imagine you're stretched that thin, and all of a sudden you get 2 new students who speak no English...

3) this kind of stuff is easier for me to show my kids when they know that 18 + 27 == (15 + 3) + 27 == 15 + (3 + 27). Etc. I find that they come home without the firm belief that what I just typed is true, but they're still expected to believe it. I also prefer to start with adding long lists of numbers on paper, showing how it's easier to find all the bits that make tens evenly. That gets them thinking about simpler shortcuts.

I only have two data points.

One of my kids is not all that gifted in math, but can do it with hard work. He was perpetually confused by the different methods of multiplying and dividing -- it was a demonstrable failure in teaching that we had to work hard to overcome.

My younger son finds math comes easy to him. He is bored to tears with school because they repeat the same concepts over and over in order to try these different techniques. At age 8 he asked me if he'd get in trouble for trying harder math at home. We tried to work with the school, but now focus on teaching him at home whenever he feels like doing more.