Not to be snarky, but these days Wolfram Mathematica has spoiled me so much that...

Not to be snarky, but these days Wolfram Mathematica has spoiled me so much that I use it for even simple computations like the ones is meant for. And I almost always already have it open and I don't need to wait for anything to load.

    >  1920/16*9
     1080
    >  Sin[30 Degree]
     1/2
    >  Quantity[2, "Minutes"] + Quantity[30, "Seconds"]
     Quantity[150, "Seconds"]
    >  UnitConvert[Quantity[6, "Megabits"/"Seconds"] *Quantity[1.5, "Hours"], "Gigabits"]
     Quantity[32.4, "Gigabits"]
    >  r = Quantity[80, "Centimeters"]
     Quantity[80, "Centimeters"]
    >  UnitConvert[Pi r^2, ("Meters")^2]
     Quantity[(16 \[Pi])/25, ("Meters")^2]
    >  UnitConvert[Quantity[40000., "Kilometers"/"SpeedOfLight"], "Milliseconds"]
     Quantity[133.426, "Milliseconds"]

It's more verbose to type out the units unless you use the integrated WolframAlpha query with Control-Equal.