问题
解答题
用简便方法计算. (1)(-
(2)318×(-
(3)(0.5×3
(4)0.259×220×259×643=______. |
答案
(1)(-
)4005×1620031 4
=(-
)4005×(42)20031 4
=(-
)4005×440061 4
=(-
)4005×44005×41 4
=[(-
)×4]4005×41 4
=(-1)×4
=-4;
(2)318×(-
)81 9
=318×[-(
)2]81 3
=318×(
)161 3
=316+2×(
)161 3
=(3×
)16×321 3
=9;
(3)(0.5×3
)199•(-2×2 3
)2003 11
=(0.5×
)199•(-2×11 3
)2003 11
=[0.5×
×(-2)×11 3
]199×(-2×3 11
)3 11
=
;6 11
(4)0.259×220×259×643
=0.259×643×220×259
=0.259×(43)3×410×259
=(0.25×4)9×(4×25)9×4
=4×1018.