一、计算题 (1)18×30=540 (2)120-78=42 (3)4.5+2.67=7.17 (4)5.2×0.5=26 (5)105-68=37 (6)1.65÷0.5=33 (7)0.42×200=84 (8)3.1×4.2=13.02 (9)8.7×3.4=29.58 (10)11.3+5.78=17.08 (11)89.2-45.17=44.03 (12)4.12÷0.2=20.6 (13)35.6+12.84=48.44