TL;DR: View the ruler, click the L symbol twice, then click (and drag) your mouse across the ruler to the right margin. When typing, press tab to switch to right-aligned.
We were going over some past papers in one of my lectures the other day. The questions were put up on the projector and we discussed what we would write as answers. The questions typically look like this:
Rather than answering the question, one of the students asked how our lecturer had aligned the number of marks to the right, but the rest of the question on the same line was aligned to the left of the page.