1) turn 20% into a decimal= 0.20 and now multiply it by 12.80 which is 2.56 and now subtract that by 12.80 which is 10.24 is your answer.
2)45%=0.45, 0.45*200=90 and 200-90=110 is your answer
3)10%= 0.10, 0.10*52.75=5.275 and 52.75-5.275=47.475 but you answe should be 47.47
