Chapter 1 - Introduction: Matter and Measurement - Additional Exercises - Page 38: 1.66d

$N/m^2$

We know that pressure is equal to $Force/Area$. The SI Unit for Force is the Newton, given by the variable N. The SI unit for distance is meters (m), so the SI Unit for area must be $m^2$. Therefore, the SI Unit for Pressure, given by $Force/Area$, must be $N/m^2$.