289-46-64??????????????????298+102??????????????????45×18420÷35????????????????????

发布时间:2020-08-11 16:08:49

289-46-64??????????????????298+102??????????????????45×18420÷35????????????????????154+36+46????????????????810÷45÷3.

网友回答

解:(1)289-46-64,
=289-(46+64),
=289-110,
=179;

(2)298+102,
=(300-2)+(100+2),
=(300+100)+(2-2),
=400+0,
=0;

(3)45×18,
=(45×2)×(18÷2),
=90×9,
=810;

(4)420÷35,
=(420÷7)÷(35÷7),
=60÷5,
=12;

(5)154+36+46,
=(154+46)+36,
=200+36,
=236;

(6)810÷45÷3,
=18÷3,
=6.
解析分析:(1)根据减法的性质简算;
(2)运用凑整法简算;
(3)根据积不变规律,第一个因数乘上2,第二个因数除以2;
(4)根据商不变规律,把被除数和除法先同时除以7,再计算;
(5)运用加法交换律简算;
(6)按照从左到右的顺序计算.

点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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