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用简便方法计算下面各题.①574-399②432-(154-68)③672+516-72④78+76+83+82+77+80+79+85⑤321+(729-155)⑥725÷25.

题目详情
用简便方法计算下面各题.
①574-399

②432-(154-68)

③672+516-72
④78+76+83+82+77+80+79+85 ⑤321+(729-155) ⑥725÷25.
用简便方法计算下面各题.
①574-399

②432-(154-68)

③672+516-72
④78+76+83+82+77+80+79+85 ⑤321+(729-155) ⑥725÷25.
用简便方法计算下面各题.
①574-399
②432-(154-68)
③672+516-72用简便方法计算下面各题.
①574-399

②432-(154-68)

③672+516-72
④78+76+83+82+77+80+79+85 ⑤321+(729-155) ⑥725÷25.④78+76+83+82+77+80+79+85⑤321+(729-155)⑥725÷25.
▼优质解答
答案和解析
(1)574-399,
=574-400+1,
=175;

(2)432-(154-68),
=432+68-154,
=500-154,
=346;

(3)672+516-72,
=672-72+516,
=600+516,
=1116;

(4)78+76+83+82+77+80+79+85,
=80×8-2-4+3+2-3+0-1+5,
=640;

(5)321+(729-155),
=321+729-155,
=1050-155,
=895;

(6)725÷25,
=725÷5÷5,
=145÷5,
=29.