Using a color pencil to circle Important numbers in "Workings area"

Can I use blue or red color pencil to circle the numbers in my “Workings” to stand out, to make it easy to collect them once I am putting them on consolidating or any other statements?

Would blue be better as red is used for marking.

I do all of my paper with black ballpoint and do not use any correction fluids also, this is just for my own ease.

Thank you.