re: Need Help With 2nd grade Homework

I get the point of Common Core is to make math more intuitive so students learn to do math in their head, but how does this exercise facilitate that?

This seems more like a puzzle for gifted class.

Edit: Then again, even being brought up to do addition/substraction the algorithmic way, it ALWAYS occurred to me that if you subtract number a from number b, the resulting number c’s last digit will always be 1 number higher than the last digit of number b if number a ends in a 9.

I’m surprised that that is not immediately obvious to many people.

jesus common core is retarded

544 - 329 = 215

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but it's also how I do math in my head so I kind of get it.

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This is the reason for teaching kids this way. I easily do tons of math in my head. All the stuff everybody has a fit over is exactly how you do it in your head. It teaches the kid to understand the numbers. Most people just hate it because they don't understand it.

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I don’t see the need for that to even be taught at a young age. In reality they should discover it by themselves with just a curiosity in math facilitated by the prioritization of its learning and emphasis on its value.

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But obviously this has not been the case. The great majority of adults of all ages have a very poor understanding of math and cannot do %'s, easy addition and subtraction in their head even though it's a very useful skill. The idea is that what we have been teaching for years has not worked very well for most people. Therefore, lets try to teach them how to do it. I believe it will help.

Wait til you see how they do division. Tried to help my grandson but he basically told me to frick off. They use a whole sheet of paper for each problem. You'll see it soon.

I added all the circles and then subtracted the ones with lines through them.

500+25+14= 539
300+15+9= 324

539-324= 215