Can somebody help me please I think I have the problem right but I am not sure I just need to see if I have these two problems right??

Calculate the atomic mass of bromine. the two isotopes of bromine have atomic masses and relative abundance of 78.92 amu(50.69%) and 80.92 amu (49.31%)

The element copper has natural occuriing istopes with mass numbers of 63 and 65. The relative abundance and atomic masses are 69.2% for mass=62.93amu, and 30.8% for mass=64.93amu. Calculate the average atomic mass of copper.