7.42÷0.7-7.5×1.2=1.06-9=-7.945/7×7.5-5/7+5/7×3.5=(7.5-1+3.5)×5/7=10×5/7=50/73÷[(4/5-1/2)÷1/2]=3÷[3/10÷1/2]=3÷3/5=5