Air density

Hi I'm a bit confused on how to calculate the air density, where do the numbers come from to calculate thanks

Air Density is Absolute Air Pressure / Specific Gas Constant x Air Temp (°R)

We know under standard conditions 14.7 PSI is absolute air pressure, 2.7 is the specific gas constant and air temp is 519 °R (this is using 59 °F)

The answer you will get is 0.076 lb/cu ft.

Sorry I'm new to this.

Im still confused on how i find the air density,.

I have a side mount supercharger, how do I calculator the air going In , I need to understand this more clearly. Do I need a pressure gauge. Thank you