(1)如果A÷B=60,那么(A×3)÷B=A÷B×3=60×3=180;
(2)如果A×B=300,那么(A×2)×(B×2)=(A×B)×(2×2)=300×4=1200;
(3)如果A×B=600,那么(A×5)×(B÷5)=A×5×B÷5=(A×B)×(5÷5)=600×1=600;
(4)如果A÷B=75,那么(A×10)÷(B×5)=A×10÷B÷5=(A÷B)×(10÷5)=75×2=150;
(5)如果A÷B=75,那么(A÷5)÷(B÷3)=A÷5÷B×3=A÷B÷5×3=75÷5×3=45;
故答案为:180,1200,600,150,45.