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(1)79.76+84.7×0.2(2)15.37+28.44+12.56×1.25]×1.2.

编辑:chaxungu时间:2026-04-27 11:56:14分类:小学数学题库

(1)79.76+84.7×0.2(2)15.37+28.44+12.56
(3)(2.3×8.8-2.3×0.8)×1.25(4)[5.2-(2.5+7.5÷5)]×1.2.
解:
(1)79.76+84.7×0.2,
=79.76+16.94,
=96.7;

(2)15.37+28.44+12.56,
=15.37+(28.44+12.56),
=15.37+41,
=56.37;

(3)(2.3×8.8-2.3×0.8)×1.25,
=2.3×(8.8-0.8)×1.25,
=2.3×8×1.25,
=2.3×(8×1.25),
=2.3×10,
=23;

(4)[5.2-(2.5+7.5÷5)]×1.2,
=[5.2-(2.5+1.5)]×1.2,
=[5.2-4]×1.2,
=1.2×1.2,
=1.44.
分析:(1)先算乘法,再算加法;
(2)根据加法结合律进行计算;
(3)根据乘法分配律进行计算;
(4)先算除法,再算加法,再算减法,最后算乘法.
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.