Well, single digit percentages are easy. If it helps, move your decimal to the right so 9% becomes 90%. You can probably calculate 90% of 3 because you can do 10% and subtract it and get 2.7. Now move your decimal back to the left and you get 9% of 3 which is 0.27. You can do the same with higher percentages once you learn to break them in to 10% pieces.
I’d… probably use the calculator app before I do all this mental gymnastics
This is not mental gymnastics.
This is a coherent method and makes a lot of sense.
Mental gymnastics is when someone has to lie to themselves to make a point that isn’t correct. Like when people argue that trump was a good president because they can list several good things he did.
Or when people claim something is mental gymnastics when it’s actually called maths.