This post is part of a series outlining No More Marking’s initial findings from a mathematics research project, carried out jointly with Axiom Maths, in 2023-2024. You can find the previous post on the multiple-choice assessment here. As part of the project, Year 7 students took part in a comparative judgement assessment of mathematical reasoning skills using the No More Marking platform. In the assessment, students were asked to answer two questions:
"Once again, the student is approaching fully correct answers, although technically, the first question is not quite correct (some of the examples, e.g. 9 + 9 + 6, did not use different single digits)."
This just seems flat-out wrong to me. The original problem statement did not require the digits to be different; instead, it only required that the 3-digit numbers are distinct:
"The digits of the 3-digit whole number 384 add up to 3 + 8 + 4 = 15. How many different 3-digit whole numbers can you find whose digits add up to 24?"
So 9 + 9 + 6 is in fact a perfectly valid solution to this problem.
"Once again, the student is approaching fully correct answers, although technically, the first question is not quite correct (some of the examples, e.g. 9 + 9 + 6, did not use different single digits)."
This just seems flat-out wrong to me. The original problem statement did not require the digits to be different; instead, it only required that the 3-digit numbers are distinct:
"The digits of the 3-digit whole number 384 add up to 3 + 8 + 4 = 15. How many different 3-digit whole numbers can you find whose digits add up to 24?"
So 9 + 9 + 6 is in fact a perfectly valid solution to this problem.