Comment by crooked-v

Not that poster, but for me it's directly manipulating numbers (for example, "16×3 + 5" turns into "10×3 + 6×3 + 5" into "30 + 18 + 5" into "30 + 10 + 8 + 5" into "40 + 13" into "53"). There's no language involved, though in some cases I might use some spatial reasoning by doing something like associating given chunks of an equation with different fingers.