Need 4th grade math help please! ASAP

[Lintasare]

I am wondering why you didn't just subtract the 68 out longhand and forget the calculator. In 4th grade you should not be using a calculator. I didn't start using a calculator for math until my junior year of high school and that was because I needed the graphing function.

Whatever happened to doing math the old fashioned way with a pencil and paper?

68+x=413
x=413-68
x=345

 

[Disney Ella]

I am wondering why you didn't just subtract the 68 out longhand and forget the calculator. In 4th grade you should not be using a calculator. I didn't start using a calculator for math until my junior year of high school and that was because I needed the graphing function.

Whatever happened to doing math the old fashioned way with a pencil and paper?

68+x=413
x=413-68
x=345

I don't think the calculator is actually broken, but that the students are supposed to pretend a key doesn't work and must figure out an alternative way of solving the problem using the calculator without the working key. OP, is this Everyday Math?

 

[tw1nsmom]

Both of my children are in the 4th grade and can I say that I HATE, HATE, HATE this kind of math! They spend so little time learning a straight forward way of solving problems and then they come up with lesson after lesson of these roundabout methods. I know what they're going for. I actually have a masters in elementary education. However, when most of the children have shaky basic skills they are just confused by all these odd methods.

 

[chisnpeke]

I am wondering why you didn't just subtract the 68 out longhand and forget the calculator. In 4th grade you should not be using a calculator. I didn't start using a calculator for math until my junior year of high school and that was because I needed the graphing function.

Whatever happened to doing math the old fashioned way with a pencil and paper?

68+x=413
x=413-68
x=345

This is what I was wondering. I am terrible at math but this seemed to be the easiest solution.

 

[jenlynn0808]

You are doing Everyday or Chicago Math right? I taught 4th grade for 10 years and have taught this several times. Basically it is a guess and check type of problem. This is how I would have taught it to my class:

68+x=413: I start by telling my class to use what you know and remember to be simple (becasue when you get to complex, you can make silly mistakes), you have 68 and you need to get to 413, so we start with a guess of 400 (68+400=468) so 400 is to high, then they usually guess 300 (68+300=368) so our guess is to low. Then I ask the class what they think is an easy munber to add but is between 300 & 400. I get a few shouts of 350, so we plug that in to the equation (68+350=418). All right so now we know 350 is to high, but it is very close, what shoudl we try next? Now I get shouts of 340 or 345, depending on time, it determines which number I plug in next. My board would look like this:

68+400= 468 (an arrow pointing up-shows guess is to high)
68+300= 368 (an arrow pointing down-shows guess is to low)
68+350= 418 (an arrow pointing up-shows guess is to high)
68+340= 308 (an arrow pointing down-shows guess is to low)
68+345= 413 (Star-shows guess is right on)
x=345

HTH

 

[Lisa loves Pooh]

Subtract it using pencil and paper.

Just b/c he can use a calculator, doesn't mean that he has to or that he should.

As someone posted....413-68 = ......


We homeschool and dd has been begging to use a calculator and I have banned them until she's doing much more complex problems.

A calculator is USELESS if you don't know how to do basic math, b/c then how on earth will you notice something is wrong?

 

[Lisa loves Pooh]

Thanks for that idea, but since it is 4th grade, I don't think algebra is the answer. They have no concept of algebra. Plus in order to enter a negative you need the - key, and that's broken!

Actually--elementary students can very much understand algebra. My kids have been learning basics since grade-K in their math program. Now we do not go through the complexities of a full scale algebra problem....


But a 2 + ___ = 6 doesn't stump them.

So kid--2 plus what = 6, and they come up with 4.

20+ what = 60

Same deal and they come up with 40.

No need to go through the formulas and properties. This is simply extremely basic algebra that will help them when they have to learn all the rules and formulas.

For his problem....68 plus what = 413. Subtract 68 from 413 to find the answer. If he could have done it on a calculator, he woudl have done the same thing. Now he just does it on paper.

 

[FireDancer]

A calculator shouldn't be needed to subtract two whole numbers, even by a 4th grader. If you have to use a calculator just enter 413 + 68 (press +/- key) and you will have your answer. Adding a negative number to a positive number is the exact same as subtracting.

If you have no +/- key get a better calculator.

You are posing this on a computer so it has a calculator. Click start -> Run -> type 'calc' -> hit enter.

 

[ICF]

People----no actual calculater was harmed in the making of this math problem. There is no 'real' broken calculater.

 

[The Mystery Machine]

People----no actual calculater was harmed in the making of this math problem. There is no 'real' broken calculater.

It took me awhile to understand what she meant.

You have to solve the problem without using subtraction for those who did not get that part of the homework assignment.

 

[damo]

Lol. This is a funny thread. People need to go reread the original post and see that the child is SUPPOSED to use the "broken calculator".

I think the question is just trying to get them to use trial and error to find the right answer by adding different numbers to 68 and get to 413, using some smart estimating.

 

[DBL101]

This is Everyday Math? Guessing? I sure hope it doesn't evolve into Everyday Medicine. I'd hate to have the doctor guessing? What do they do if they kill off all of their patients before guessing correctly?

 

[maelstrom]

You are doing Everyday or Chicago Math right? I taught 4th grade for 10 years and have taught this several times. Basically it is a guess and check type of problem. This is how I would have taught it to my class:

68+x=413: I start by telling my class to use what you know and remember to be simple (becasue when you get to complex, you can make silly mistakes), you have 68 and you need to get to 413, so we start with a guess of 400 (68+400=468) so 400 is to high, then they usually guess 300 (68+300=368) so our guess is to low. Then I ask the class what they think is an easy munber to add but is between 300 & 400. I get a few shouts of 350, so we plug that in to the equation (68+350=418). All right so now we know 350 is to high, but it is very close, what shoudl we try next? Now I get shouts of 340 or 345, depending on time, it determines which number I plug in next. My board would look like this:

68+400= 468 (an arrow pointing up-shows guess is to high)
68+300= 368 (an arrow pointing down-shows guess is to low)
68+350= 418 (an arrow pointing up-shows guess is to high)
68+340= 308 (an arrow pointing down-shows guess is to low)
68+345= 413 (Star-shows guess is right on)
x=345

HTH

And what is the point of this? I'm honestly curious what they hope to achieve with this stuff.

 

[tchrrx]

And what is the point of this? I'm honestly curious what they hope to achieve with this stuff.

I am also curious as to what the point is. I began basic equations (n+3=7x2) with my 3rd graders last week. If they know how to solve it using algebraic steps, why confuse them?

 

[Liberty Belle]

People----no actual calculater was harmed in the making of this math problem. There is no 'real' broken calculater.

 

[jenlynn0808]

I am also curious as to what the point is. I began basic equations (n+3=7x2) with my 3rd graders last week. If they know how to solve it using algebraic steps, why confuse them?

I think it has something to do with the spiralling curriculum that everyday math utulizes. It also comes back up when the kids are doing rate tables (near the end of the 4th grade series Unit 11 or 12-I think).

 

[Silent1CB]

What happened to teaching how to do math in your head or on paper?

No broken keys, dead batteries, or dark rooms to cause calculator problems.

Maybe THAT's the answer the teacher is looking for!

 

[Schmeck]

They are doing it in their heads and on paper - Everyday Math gets them to think outside of the didactic math box. There are multiple ways to approach a single math problem. Not everyone does it exactly the same way, so this is just a different strategy compared to using straight subtraction.

 

[jenlynn0808]

What happened to teaching how to do math in your head or on paper?

No broken keys, dead batteries, or dark rooms to cause calculator problems.

Maybe THAT's the answer the teacher is looking for!

Actually this does start out with them doing it in their heads. Then the problems start getting more complicated like a 3 digit by 3 digit multiplication problem and the division key is broken. So then the series lets them use calculators (and I have had kids that did do it in their heads-which I was fine with). Once the kids have the concepts down, basically all the calculator does is speed up the work. They, the students, need to know how to do the formulas in order to do it on the calculator. If they don't get the concepts, the calculator isn't going to help them.

 

[jenlynn0808]

They are doing it in their heads and on paper - Everyday Math gets them to think outside of the didactic math box. There are multiple ways to approach a single math problem. Not everyone does it exactly the same way, so this is just a different strategy compared to using straight subtraction.

Exactly! We teach four different ways to multiply, 2 different ways to divide, different ways to add and subtract. We all do it different in our heads.