Ответ:\(0{,}0000321=3{,}21\cdot10^{-5}\).\(0{,}000074=7{,}4\cdot10^{-5}\).\(31\frac25=31{,}4=3{,}14\cdot10^1\).\(1401\frac3{25}=1401{,}12=1{,}40112\cdot10^3\).