(9-0.6*3.2)÷1.5
= 9÷1.5 - 0.6×3.2÷1.5
= 6 - 0.32×6÷1.5
= 6 - 0.32×4
= 6 - 1.28
= 4.72
20.5 - (3.64+2.8)÷0.4
= 20.5 - (3.64÷0.4 + 2.8÷0.4)
= 20.5 - (9.1+7)
= 20.5 - 16.1
= 4.4