Math Problem - Help

I need help with my 2nd Grade granddaughters homework.


Use three different numbers between 0-10. Use the numbers once each to complete the addition chart so that the sums when added down and across equal 20.

the answer box is a square divided into 9 cubes, 3 across and 3 down.

0a0
000
00x

a = 1
x = 20

 

each row vrcfor and col vector must equal 20.

the numbers a and x already being defined places some constraints that actually make it much easier.

Code:

19 1 0

Code:

1 19 0

Code:

0 0 20

edited to fix the matrix (it wasn't formatted correctly and looked wrong)

this i believe is the only possible solution because the bottom row and right column can only contain 20 and two zeros. after filling the matrix with those numbers then 19 is the only number that will sum to 20 for the middle column. the number to the left in the middle column, 2nd row must be 1 in order to sum to 20. this on,y leaves one possible solution for the 1st row, 1st column [19].

I think there's an error in the question though, this cannot be done with numbers if the range is only 1-10. since each vector must sum to 20, x=20 necessarily restricts the other numbers in the vector containing x to 20.

there is no integer <10 that sums to 20 when added to one (a =1). these constraints only allow freedom to pick a single number for the top row.

if that's really what the question says (numbers between 1 and 10) then my answer would be "no solution".

 

Yes, you can only use each number once.

This problem is ridiculous.

I searched the internet and saw at least one more person asking for help.

 

The answer is that your grand daughter's teacher is smoking crack.

Let's give each cube a letter.

A B C
D E F
G H I

According to the description, the value in cube B is a=1, and the value in cube I is x=20. If the instructions are to "complete the addition chart so that the sums when added down and across equal 20 ", this means that A+B+C, D+E+F, G+H+I, A+D+G, B+E+H, and C+F+I must all equal 20.

If the value in cube I must be 20, that means that the values in C, F, G, and H must be zero, assuming that negative values can not be entered.

If the value in cube B must be 1, and C and H must be zero, that means that value in cube E and A must be 19. The instructions clearly state "Use three different numbers between 0-10. Use the numbers once each", which is not possible, even if you could enter more than one number in each cube.

 

Thanks guys~!!!

 

this is exactly why i didn't enjoy math in school much. seemed like a whole lot of busy work to me, this type of problem mostly amounts to guessing, and i'm actually fairly sure that there isn't a solution that fits the criteria of the question (especially not one on a second grade level)

unless they are teaching algorithms, this problem serves little purpose for learning basic arithmetic. (basically just a time waster to keep kids busy).

i'd answer with "no solution", if there is a solution i'd love to knwo what it is.

 

It's coming out of that damn core curriculum.

I saw another mother asking on another forum.

 

If all else fails, throw in the answer as xsquared.

Those bloody x's ways getting squared.

 

I don't think that the problem is core curriculum in this case, but rather teacher error

 

It's on a copied sheet somewhere that's getting passed around. I saw it as a forum question somewhere else in 2009.

http://67-72chevytrucks.com/vboard/showthread.php?t=328481

It's funny. It's on a chevy forum.

 

that wouldn't work either cuz x=20.

might as well just play sudoku ...

 

is this common core math? I really hope they do away with that shit before my kid starts school. This is the type of thing that makes so many children hate math.

 

The triplets are in the "Talented And Gifted" classes in 2nd Grade.

The parent I saw asking in 2009 on the other forum was asking for their 3rd Grader.

My grandson is in the regular 2nd Grade classes. I'll be ready if they get around to throwing this question at him, lol.

 

Oh well if x = 20 then just Pythagoras that motherfucker, MC2, and then algebra. :d

 

the answer is this



you aren't supposed to help children with their homework or the teacher has no way of gauging where the kids strengths and weaknesses may lie....

todays parent just did this a month back

 

Also the back of the book. Answers were always there when I went to school. :d

 

when you cheat in school your only cheating yourself out of knowledge.

 

You are supposed to help with homework. It's part of the teaching process.

Tests guage what the child has learned.