normally you do
find tax of meal
find tip of meal not include tax
add them
percent means partts ouf ot 100 so
6.5%=6.5/100=0.065
and 20%=20/100=0.2
so
tax of meal=65.8 times 0.065=4.277
round to 4.28
tip=65.8 times 0.2=13.16
add
65.8+4.28+13.16=$83.24