Pressure and area each visibly change force. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Base patch gives eighteen newtons
Pressure 6 pascals over area 3 square metres gives force 18 newtons.
F=6×3=18
Lower pressure lowers the force
Pressure 4 pascals over area 3 square metres gives force 12 newtons.
F=4×3=12
Wider area raises the force
Pressure 6 pascals over area 5 square metres gives force 30 newtons.