Why 5+5+5 doesn’t always make 15: Maths exam question divides the internet

[flitox]

i had the curiosity of hear how you us/english (?) people learn table of 3 and here it is:

http://dai.ly/x1cq0ef

like here, you say 3X1, 3X2, 3X3 etc so the teatcher can only be wrong in his thinking cuz we all know tabke of 3 is 3; 3+3; 3+3+3 etc while according to him, it should be 1+1+1; 2+2+2; 3+3+3 etc and that we all know it's not table of 3

and like someone say a bit above, it doesn't change a thing if we write 3X5 or 5x3 (just an example 2+3x5 & 2+5x3 make the exact same result) so if the teacher wanted to make his pupils think a bit, he should have asked for the 2 possibilities

[dMog]

i had the curiosity of hear how you us/english (?) people learn table of 3 and here it is:

http://dai.ly/x1cq0ef

like here, you say 3X1, 3X2, 3X3 etc so the teatcher can only be wrong in his thinking cuz we all know tabke of 3 is 3; 3+3; 3+3+3 etc while according to him, it should be 1+1+1; 2+2+2; 3+3+3 etc and that we all know it's not table of 3

and like someone say a bit above, it doesn't change a thing if we write 3X5 or 5x3 (just an example 2+3x5 & 2+5x3 make the exact same result) so if the teacher wanted to make his pupils think a bit, he should have asked for the 2 possibilities

as far as i understand math...and as far as math teachers teach it...the teacher was correct...the student got the correct answer but did so by slightly incorrectly interpreting the equation

[hawk007]

I can say, the teacher didn't actually want the result 15, rather, they tested whether the students perceived the Arithmetic Operations correctly, or not.

I was a mechanical engineering student 15 years ago. Had to deal with many design related problems. If the interpretation of any particular problem was correct in the answer sheet, but, the result is incorrect somehow, that didn't prevent us to get the full marks. And, the reverse was also true.

[flitox]

so table of 3 is

1+1+1

2+2+2

3+3+3

4+4+4

5+5+5

...

10+10+10

and not

3

3+3

3+3+3

3+3+3+3

...

3+3+3+3+3+3+3+3+3+3

no math theacher here????