Start at 27

27+3=30

30+20= 50

50+2= 52

3+2+20= 25

Ok am I the only one thinking that that's horse poop?

I'm not great with math and I admit that but this is my approach:

52-27

12-7=5

40-20=20

20+5=25

My husband who is an engineer said that he would Solve 52-27 like this:

52-7=45

45-20=25

We both find the above way very long and has unnecessary steps.

The reason I ask is because on another board the teacher said that this was the method that people with strong math concepts use to figure out problems in their head.

Also I see this frequently as CC aligned or how the CC says to figure out these problems. To me all those steps are confusing. I dunno... I just don't get it.

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I have a friend that says that's the way she thinks them out in her head, so she was pleasantly surprised to find that she could understand the CC math that her kids were bringing home.

However, I refuse to teach my kids that. I show them shortcuts, of course. IF they choose to use them when figuring math problems, that's just fine. That's how I feel about the common core crap. Just teach it straight:52-27 starting with the ones then tens... If they come up with a way to figure it out in their head faster, then awesome. But it should be left to each kid to figure out how their brain works. Show them shortcuts, sure, but don't make it standard.

Quoting Jlee4249:I have a friend that says that's the way she thinks them out in her head, so she was pleasantly surprised to find that she could understand the CC math that her kids were bringing home.

However, I refuse to teach my kids that. I show them shortcuts, of course. IF they choose to use them when figuring math problems, that's just fine. That's how I feel about the common core crap. Just teach it straight:52-27 starting with the ones then tens... If they come up with a way to figure it out in their head faster, then awesome. But it should be left to each kid to figure out how their brain works. Show them shortcuts, sure, but don't make it standard.

I use Math U See and so far this stratedy hasn't been used and I don't plan on teaching it. I was just wondering what others thought of it and if it was the normal way to go about figuring out those type of problems.

I get why she says that. D and I both tend to like adding more than subtracting. Plus it is how I figure out how much change I should get. Not everyone is going to see it that way though. Nothing should be standard, teach kids a bunch of different ways and let them use the one that sticks.

I counted by 10's starting with 27- 37, 47 (that's 20) then 48, 49, 50 , 51, 52 (that's 4) So the answer would be 24.

Edit I meant 5! I Haven't had my coffee yet,lol.

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52-27

I would do 52-20=32

Then I would 32-7=25

Most mathematicians tell you simplify it. Do not make it more complicated. Mathematical is more important than getting the right answer.

I agree with Jen! Anyone with a strong math foundation should know that there are many ways of solving math problems. If a teacher is using the CC "scare tactics" to make it seem like there is only one solid way of doing mental math, she should be ashamed of herself!

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- chotovec82

on Mar. 11, 2014 at 1:03 AM