7×40＝680,100－63＝37,3.2＋1.68＝4.88,2.8×0.4＝ 1.12 14－7.4＝6.6,1.92÷0.04＝48,0.32×500＝160,0.65＋4.35＝ 5 10－5.4＝4.6,4÷20＝0.2,3.5×200＝700,1.5－0.06＝1.44 0.75÷15＝0.05,0.4×0.8＝0.32,4×...