302×58=300×58+2×58运用 律使计算简便.已知192÷16=12,我很快得出1.92÷1.6= .
3:2==15÷ = %= (填小数)
4÷ ==12.5%=3: =.
0.625= ÷40=40: == %.
:5=0.8== ÷20= %.
2: =4÷ === %, .