Spoiler alert: you need to use paper as though it matters.
Yeah, of course they won’t collect your scratchwork, so in that sense you don’t need to do it. And yeah, of course, you can do work in your head faster than you can on paper.
But here’s the thing. When you do work in your head, you make little mistakes. Not many, maybe, but they add up. And here’s the other thing. Writing things down doesn’t take as long as you think it does. Plus, writing things down lets you check your work and think things through more clearly.
It all adds up to one thing: if you do your work on paper, you’ll get a higher score overall.
Don’t believe me? That’s fine. So put it to the test:
Try doing one timed test where you do everything in your head, and a second one where you write all your thoughts and calculations on paper. Here’s what I bet will happen: the test you did in your head will feel better, will feel faster, will seem so obviously better that you will swear that the test you did in your head will be the one with the higher score.
And then you’ll check your scores and discover that you were wrong about that.
And then you’ll re-check your scores because you won’t believe it.
And then you’ll look back at the test you did in your head and notice the mistakes you made.
And then you’ll wonder how you did that.
And then you’ll be tempted not to count those as wrong answers. Because you knew what you were doing; you just messed up on something small.
So pay really close attention here: small mistakes are the main reason people underperform on the AMC 8.
So, don’t make that mistake. Instead, use your scratch paper as though it matters. Because it does matter.