77x(9/55-9/77)
=77x9/55-77x9/77
=7x9/5-9
=9x7/5-9
=9x(7/5-1)
=9x2/5
=18/5
0.4x(3.2-0.8)÷1.2
=0.4x2.4÷1.2
=0.4x2x1.2÷1.2
=0.8
(7/8-5/16)x(5/9+2/3)
=﹙14/16-5/16﹚×﹙5/9＋6/9﹚
=9/16×11/9
=11/16
3.6÷1.2+0.5x5
=3＋2.5
=5.5
4/5x2/3+1/5÷3/4
=8/15＋1/5x4/3
=8/15＋4/15
=12/15
=4/51/5÷[(2/3÷1/5)x1/3]这个1/5÷[(2/3÷1/5)x1/3]=1/5÷[2/3×5×1/3]=1/5÷10/9=1/5×9/10=9/501/2+1/3÷2/3=1/2＋1/3×3/2=1/2＋1/2=1