1-0.001= 1÷4= 0.9+0.1÷0.1=
9÷0.6= 12×0.05= 1.4-1.4÷7=
2.5×4×0.8= 3.6÷0.7≈ (得数保留一位小数)
①4.56-(1+0.4)×3.2
②73×1.61+1.61×28-1.61
③6.24×8×(0.47+0.25+0.53)
④38.4÷0.16-6.8×35+7.8