Anyways, as I said before, photons dont have any rest mass (Invariant mass), however they have relativistic mass (Variant mass). At least that that is what currently is believed, however the rest mass of photons has only been measured to be <1×10−18 eV according to Wikipedia. There is currently no known method that I know of that would be able to show that the rest mass is 0, including measuring the mass of stars, however the rest mass is believed to be zero because it makes a lot of things simpler. Also, could you please stop doing simple arithmetic errors for no reasons, it is just irritating.