(-2/5)²除以（-4² +10）
=4/25÷(-6)
=-4/25×1/6
=-2/75
（-5/9+1/8-3/4)除以（-1/8)2
=（-5/9+1/8-3/4)除以1/64
=（-5/9+1/8-3/4)×64
=-5/9×64+1/8×64-3/4×64
=-320/9+8-48
=-35又5/9-40
=-75又5/9
(1/2-2/3)除以（-1/6)-(-4)2x(3/8-1)
=-(1/2-2/3)×6-16x(3/8-1)
=-(1/2×6-2/3×6)-(16x3/8-16x1)
=-(3-4)-(6-16)
=1+10
=11