When inputting the numbers in the calculator can i also please see how one would input the numbers when solving the predicted pressure using van der walls equation?

At relatively low pressures and high temperatures the Ideal Gas Law is a reasonably good approximation for most gases. 
A better general approximation, which becomes increasingly important as gases are compressed, is given by the van der Waals equation. 
The observed pressure for a pure gas can be expressed as: 
1.553×10^-1 mol of argon (Ar) gas is isolated in a chamber of volume 20.00 mL at -67.3 °C. 
Calculate the predicted pressure in the chamber using first the ideal gas law and then the Van der Waals equation. 
(For Ar, the Van der Waals constants are: a = 1.35 atm L² mol^-2; b = 0.0322 L mol^-1.) 
Enter the numerical value (in either decimal or scientific notation) for the ratio, [(P_vdW)/(P_ideal)].