Is knowing how to calculate more important than the actual calculation?

If you are confused, let's say I know how I can get the answer for the area of the circle, but I can't calculate it without pen and paper. I just use calculator the entire time. I can't calculate in my mind because I just suddenly forget the number i have calculated. But I know how I can calculate. I know the formula for geometry, y gradient, and some physics formula. I also know how to do linear equations. I might be dumb.

Is remembering the formulas more important than calculating?