For very large numbers, it is much more convenient to use scientific notation. To do this, detect first the position of the decimal point. For whole numbers, the decimal point is place implicitly after the very last digit. Then, move this decimal point to the left until you reach to the last digit. In this case, you moved 8 places until you reach 6.4. Because the number is more than 1, the exponent would have a positive sign. Hence, the scientific notation would be 6.4×10⁸.
Radio waves
Radio waves, on the other hand, have the lowest energies, longest wavelengths, and lowest frequencies of any type of EM radiation. In order from highest to lowest energy, the sections of the EM spectrum are named: gamma rays, X-rays, ultraviolet radiation, visible light, infrared radiation, and radio waves.
You are good enough in general. As long as you know and feel that you are good enough within yourself, you won’t have to worry about meeting anyone else’s expectations. Maybe it’s your mom.. not you.