1) 20% off $12.80

2) 45% off $200

3) 10% off $52.75

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