This task differentiates learning by giving keener students the chance to show their understanding by doing fewer (but more challenging) problems. For grading students work, I usually give "all the points" or "half the points" for a partially correct solution. You could break it into quarters if you need to be more specific :)
You can edit the .docx version to suit your specific class needs. This makes a great exam review, even if you don't wish to use it for evaluation purposes!
.docx and .pdf file versions
This task aligns to the Ontario Curriculum for grade 10 academic math (MPM2D)