# Public school math is confusing...

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that is soooo confusing for kids .. my daughter did this one yr in public school and was thrown off that kids coudn't get the first part lol ... she would just solve problem and get bad grade because they wouldn't explain , but she knew what the math problem was lol ... good reason we don't do that anymore ;)

Do they always have to show 2 ways to do it? Do they have to show it as breaking into tens and ones? Can they break it into other "friendly" numbers?

My son understood it better when talking about subtraction. My suggestion is to break out the base ten blocks and go over problem after problem. :-(

Her mom could email the teacher for a kid-oriented approach. This way they r teaching it the same way.

I know before doing mental math like that, my kids drilled extreme skip counting... not just by 2s 5s 10s... but starting at 2, skip count by 5s....

2, 7, 12, 17, etc.. then backwards til they could rattle off almost any skip count challenge. This laid groundwork for their ability to visualize mental math patterns.

Quoting No_Difference:I was able to figure it out, but I don't know how to explain it at a level she can udnerstand it. Know what I mean? I've tried showing her with blocks, writing it with her on a marker board, and doing just random problems that were even easier than those on her worksheets... She's not grasping it at all and I'm running out of ideas.

Quoting KrissyKC:

The top one, I know, they are just breaking it down to tens plus ones... so they can learn to mentally add quickly. My daughter (10) has been exposed to that in little bits over the years.

The second one, I started to say I had no clue, but I think what they are doing is mentally rounding the 43 to the nearest five (by adding two)... so you have to subtract two from the sixty seven.... to get 65... this way you can mentally add 45+65 = 110 easier than you can mentally add 43 + 67 = 110.

I, personally would have rounded to the nearest ten instead of five... So I would have added 7 and subtracted 7, to get 40+60 to get 110 MUUUCH easier.

the plus side is, its just a brief section in most curriculum, and if the kid just cant do it... its not like the old fashioned approach doesnt work.

We also learned casting out nines... any one ever heard of that??? i had to google it for a few days because i didnt get what rod and staff was teaching.

Actually that is sort of the way I already do math. I add the ones first, then the tens, then the hundreds and so on, then I add all that up. The difference is that I don't think 43 = 40+3 and 67=60+7. I just think 7+3+10, I usually carry the one but sometimes I won't. Then I have 4+6=10. I know that 10 10's equals 100 so 100+10 is 110. It's much quicker when I do it in my head.

I also sometimes do think sort of like the second way too. It's easier to add with 5's or 10's, so I might "borrow" 2 from the 7 to make it 45+65. Or I might "borrow" all 3 and add them to the 7 to make another 10, then I have 40+60+10 which again is easier. My DS counts up in his head. 67, 68, 69, 70. 70, 80, 90, 100, 110. I hope when he has to take the state test sometime this year, he won't have to show his work and can just give them the answer.

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- No_Difference

Silver Member on Oct. 11, 2012 at 8:41 AMThank you :) That's essentially the same thing I told her last night and I think the bulb started to turn on in her head. She was able to do 2 correctly by hersef at least for writting it out, but the rest of it still had her lost. But we made progress!! LOL I'll take it :). I'm just really hoping now I can get her mom t come over and all of us work on it so that her mom can see what we're doing because Ithink we're getting somewhere.