题目内容

计算下面各题,能简算的要写出简算过程.
①6.72+2.08×4×1.5
②12.56÷2.5÷0.4
③2.85×4.7+28.5×0.53
④9.88÷[5×(7.34-6.96)]
⑤2.5×3.2×1.25
⑥0.56×99.

解:①6.72+2.08×4×1.5,
=6.72+2.08×6,
=6.72+12.48,
=19.2;

②12.56÷2.5÷0.4,
=12.56÷(2.5×0.4),
=12.56÷1,
=12.56;

③2.85×4.7+28.5×0.53,
=2.58×4.7+(28.5÷10)×(0.53×10),
=2.58×4.7+2.85×.5.3,
=2.58×(4.7+5.3),
=2.58×10,
=25.8;

④9.88÷[5×(7.34-6.96)],
=9.88÷(5×7.34-5×6.96),
=9.88÷(36.7-34.8),
=9.88÷1.9,
=5.2;


⑤2.5×3.2×1.25,
=(2.5×0.4)×(8×1.25),
=1×10,
=10;


⑥0.56×99,
=0.56×(100-1),
=0.56×100-0.56,
=56-0.56,
=55.44.
分析:①6.72+2.08×4×1.5,按运算顺序算,算乘法时可利用乘法结合律先算4×1.5;
②12.56÷2.5÷0.4,可利用一个数连除以两个数等于这个数除以这两个数的积;
③2.85×4.7+28.5×0.53,先利用积不变规律,再利用乘法分配律进行简算;
④9.88÷[5×(7.34-6.96)],中括号里利用乘法分配律进行简算;
⑤2.5×3.2×1.25,得用乘法结合律进行简算;
⑥0.56×99,先把99看成100-1,再利用乘法分配律进行简算.
点评:此题考查了在计算过程中如果有简便的算法简算会更快更准确,所以平时要把基本的方法掌握好.
练习册系列答案
相关题目

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网