能简便的要简便计算2.9×1.4+2×0.16????????200-(3.05+7.1)×18??????????2.5×32×1.25(2.44-1.8)÷0.4

发布时间:2020-08-07 12:34:41

能简便的要简便计算
2.9×1.4+2×0.16????????200-(3.05+7.1)×18??????????2.5×32×1.25
(2.44-1.8)÷0.4×20??????????48×10.1????????????????3.2×19+3.2.

网友回答

解:(1)2.9×1.4+2×0.16,
=4.06+0.32,
=4.38;

(2)200-(3.05+7.1)×18,
=200-10.15×18,
=200-182.7,
=17.3;

(3)2.5×32×1.25,
=2.5×4×8×1.25,
=(2.5×4)×(8×1.25),
=10×10,
=100;

(4)(2.44-1.8)÷0.4×20,
=0.64÷0.4×20,
=1.6×20,
=32;

(5)48×10.1,
=48×(10+0.1),
=48×10+48×0.1,
=480+4.8,
=484.8;

(6)3.2×19+3.2,
=3.2×(19+1),
=3.2×20,
=64.
解析分析:(1)先同时运算乘法,再算加法;
(2)先算小括号里面的加法,再算括号外的乘法,最后算减法;
(3)先把32分解成4×8然后运用乘法结合律简算;
(4)先算小括号的减法,再算括号外的除法,最后算乘法;
(5)把10.1分解成10+0.1然后用乘法分配律简算;
(6)运用乘法分配律简算.

点评:运算定律是常用的简便运算的方法,要熟练掌握,灵活运用.
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