Who can calculate faster than a calculator?
Me! I can! So can you. Its not hard, try 2 + 3. I've calculated that before you have the calculator out of your bag. Particularly if (my particular stupidity) you start typing in the calculation before turning the damn thing on.
I can prime factorise 144 in my head, way faster than you can do it with a calculator.
I can do calculus and mechanics in my head (in common with most people on Earth) so fast that I can catch a ball falling out of the sky. Your calculator doesn't even have a button for that one, & it's super hard to catch a ball while calculating speed, resistance & position on a calculator.
Calculators are really useful labour saving devices. But they're quite slow if you include the time (which you should) it takes to input the data.