DS was doing some past maths GCSE papers and we were checking the answers against the marking scheme. On one of the questions, his workings out looked a bit different to what was shown in the marking scheme. Given that there may be more than one way of arriving at the same answer in maths, should the marking scheme be interpreted as the only ‘approved’ way of doing things, or will any method do, as long as it’s logical and makes sense?
The particular question in this case was this:
The equation of a line L is x + 2y = 6 . Find the gradient of L.
DS calculated the gradient as -1/2
(written as a 'normal' fraction, not with a slanted line), using these workings:2y = -x + 6
y = -x/2 + 3
According to the marking scheme, 3 marks were to be awarded for the following workings out:
2y = 6 - x
y = 3 - x/2
y = (6 - x)/2
NB. In all cases, there was a 'normal' fraction presentation, not a slanted line; I managed to type it properly in Word, just can't get it to show here.
To my mind, DS’s and ‘official’ workings out are equivalent, although visually I prefer his version as it follows the 'y = mx + c
' format I am used to.
Would full marks for this question be given only if the workings out were shown exactly the same as in the marking scheme or would DS's version be acceptable?
Thanks in advance for any thoughts on this.