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用简便方法计算:1.29+3.7+0.71+6.3 528×78+472×78 46.5×99+46.5125×89×8 12.37-5.32-4.68 12.5×

编辑:chaxungu时间:2026-04-27 09:04:48分类:小学数学题库

用简便方法计算:
1.29+3.7+0.71+6.3    528×78+472×78    46.5×99+46.5
125×89×8        12.37-5.32-4.68    12.5×(0.8+8)解:①1.29+3.7+0.71+6.3,
=(1.29+0.71)+(3.7+6.3),
=2+10,
=12;

②528×78+472×78,
=(528+472)×78,
=1000×78,
=78000;

③46.5×99+46.5,
=(99+1)×46.5,
=100×46.5,
=4650;

④125×89×8,
=125×8×89,
=1000×89,
=89000;

⑤12.37-5.32-4.68,
=12.37-(5.32+4.68),
=12.37-10,
=2.37;

⑥12.5×(0.8+8),
=12.5×0.8+12.5×8,
=10+100,
=110.
分析:①用加法结合律简算,②③⑥用乘法分配律简算,④用乘法交换律简算,⑤根据减去两个数等于减去这两个数的和来简算.
点评:记住常用的简算方法,并灵活运用.