Help with 5th grade homework PLEASE!!!

[jacksonsmom]

I just had an ah-ha moment when reading the explanations.
THANK YOU every one for taking the time and helping me and my son with this problem.

I explained it to him and he seemed to totally get it. Took me a few more times of reading it before I finally got why the answer was 64!!!

 

[Tinkh]

I just had an ah-ha moment when reading the explanations.
THANK YOU every one for taking the time and helping me and my son with this problem.

I explained it to him and he seemed to totally get it. Took me a few more times of reading it before I finally got why the answer was 64!!!

Could you confirm after grading that the answer is for sure 64? I really do think it is 48, but like I said math is not my strongest subject. I just do not get where it can be 64. It will make me crazy until I know haha.

 

[FayeW]

Could you confirm after grading that the answer is for sure 64? I really do think it is 48, but like I said math is not my strongest subject. I just do not get where it can be 64. It will make me crazy until I know haha.

Think of it this way:

We know that he spent $16 more than half his money. In order to spend only half the money he had, he would have spent $16 less than he did, and therefore would have had $32 left in his pocket instead of only $16.

So, adding the $16 he would have had if he had spent only half his money to the $16 he did have (when he spent more than half), then he would have $32 left. If $32 equals half, then x 2 is $64

 

[georgina]

Just work the problem backwards, and you can see it is not 48. If he started with 48, he would have spent 40, and only be left with 8. Remember, he spent $16 more than half (so 16 + 24).

 

[poochie]

This is one of the many reasons I stopped trying to help with Math homework. That along with the one time I thought I had it figured out and proceeded to explain to my DS. The next day he came home and told me the teacher said not to let mom help anymore as we were totally incorrect. I believe it was about 5th grade also.

 

[Tinkh]

Think of it this way:

We know that he spent $16 more than half his money. In order to spend only half the money he had, he would have spent $16 less than he did, and therefore would have had $32 left in his pocket instead of only $16.

So, adding the $16 he would have had if he had spent only half his money to the $16 he did have (when he spent more than half), then he would have $32 left. If $32 equals half, then x 2 is $64

Ack! My head hurts trying to get this lol. I think that I see what you mean. Thanks Goodness, no clue how my 10th grader in Algebra 2 did not get it on first glance either. I am so glad that after I finished my medical math that I do not have to revisit this stuff haha.

 

[krcit]

This is one of the many reasons I stopped trying to help with Math homework. That along with the one time I thought I had it figured out and proceeded to explain to my DS. The next day he came home and told me the teacher said not to let mom help anymore as we were totally incorrect. I believe it was about 5th grade also.

I cannot do math at all! Thankfully, my oldest is great in math so she can help her younger siblings She came up with 64 also...I, on the other hand, still don't even understand the question

 

[damo]

The answer is 64.

The original amount he had - the amount he spent = 16

x - (x/2 +16) = 16
x - x/2 -16 = 16
x - x/2 = 32
x/2 = 32
x = 64

 

[LilyWDW]

Well, we can check it by reversing the sense of the answer. Start with what you THINK that he had at the beginning, and work backward to the $16 that we know he ended up with:

"Benjamin went into the store and spent $16 more then half the money he had in his pocket. This left him with $16. How much money did he have in his pocket before he went into the store?"

So, if he had $48 when he started and he spent $16 more than half of that, he would have spent: $40 (48 / 2 = 24. 24 + 16 = 40)

$48 - $40 is NOT equal to $16.

However, half of $64 is $32. Add $16 to $32 and you get a total EXPENDITURE of $48. (64 / 2 = 32. 32 + 16 = 48)
$64 - $48 = $16

If you answer $48 your calculations are valid, but you're giving a differerent answer than the one that is asked for. $48 is what he spent, not what he started out with in his pocket. This is why word problems bother a lot of people who otherwise are good at math; it seems that very often the answer that would seem to be the most logical thing to solve for in an algebraic sense is not the part of the solution that the problem is asking for. (Lucky me, I never could make sense of algebraic logic; I never could figure out what I was supposed to be looking for if the problem was just a bunch of numbers. Give me a story to go with it, though, and the answer always falls into place for me.)

This is really THE post that shows it should be $64. By working the problem backwards, you are checking your original answer. This was something that was drilled into my head as a child... ALWAYS check your answer. It really helps with word problems since so many people get mixed up with them.

 

[sunnyday123]

How old is Benjamin? I really don't think a 5th grader should walk around with $64 in his pocket.



I got nothing else.

 

[luvmyfam444]

How old is Benjamin? I really don't think a 5th grader should walk around with $64 in his pocket.



I got nothing else.

AGREED!

This just confirmed how CLULESS I am! Even the explanations didn't help a bit! AND I've got 3 standardized tests to take before Dec that will be full of questions like this.....

 

[NotUrsula]

LOL! I think I need to print off and frame this thread -- it's worth something to me to have witnesses that I CAN properly explain how I got a math answer.

I've got a monster spreadsheet for my fiscal budget to tackle at work this week -- I feel so much better about that all of a sudden!

 

[shortbun]

Fifth grade could absolutely being doing simple Algebra. They don't even call those simple solve for X problems Algebra anymore. Amazing isn't it?

 

[jacksonsmom]

Could you confirm after grading that the answer is for sure 64? I really do think it is 48, but like I said math is not my strongest subject. I just do not get where it can be 64. It will make me crazy until I know haha.

I know what you mean, for a while I was like "the answer has to be 48", but like a PP said on here, when I reserved it to check the answer it wasn't making sense. The answer couldn't be 48.
But I didn't understand how people were getting 64! I think I finally understand it, still makes my head spin though!

This pretest sheet isn't due until Wednesday so who knows when the teacher will correct it and hand it back. I will be waiting to make sure the answer is 64! lol

I hate math word problems, always have....they make my eyes go loopy!

Thanks everyone for explaining it to me, even if it was driving me batty!

 

[krcit]

How old is Benjamin? I really don't think a 5th grader should walk around with $64 in his pocket.



I got nothing else.

 

[Cinderella94]

Oh my goodness...I'm a senior in HS who's taken AP math classes and reading all of these explanations made my head hurt! .

 

[KLAIT]

Oh ya, 5th grade is absolutely beginning algebra!

 

[PUZZLDY5]

Ya'll are making my head hurt.

 

[ChrizJen]

I'm not good at math, either, but word problems involving money tend to have a solid $ answer, so they are straightforward.

"Benjamin went into the store and spent $16 more then half the money he had in his pocket. This left him with $16. How much money did he have in his pocket before he went into the store?"

As someone else pointed out, let X be the amount that he had in his pocket. (The rest of my notation is unorthodox, but I still get the correct answer.)

(X / 2) - 16 = 16

So if he has 16 now and he spent at least 16, that would mean that he started out with at least 32.

(X / 2) = 32

So, what number, divided by half, would give you 32? 64

This is how I wrote it out too. It's funny how there are several variances to getting to the same answer. I really do love algebra and the challenge of making it all work out!