Spreading a fixed force over a larger area lowers the pressure at every point, which is why a dull edge presses less than a sharp one. The inverse relation P = F / A treats the load as evenly distributed across the stated area. Real contacts are uneven, so this gives an average pressure, not a point value.
The same force spread over more area has lower pressure. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Larger area lowers pressure for the same force
Force 18 newtons over area 6 square metres needs pressure 3 pascals.