The grade boundary for an A is generally between 125-136. Let's say its the highest of 136, which is unlikely that it is because that exam was hard and the grade boundaries would probably be low. So if you got 60/100, you would need to get 76 on the calculator paper. That's definitely possible. My teacher has made a list of things that may come up on calculator because they weren't on non- calculator. For example: histograms; different types of plotting graphs; simultaneous equations; trial and improvement; transformation of graphs; upper and lower bounds; bearings; trig; plans and elevations etc. I would revise them all well, I would aim for 70% minimum for the calculator in order to get the A, and I'm thinking that the grade bounderies will hopefully be low. Don't worry about it, revise!
Hope this helps!