题目内容

脱式计算,能简算的要简算.
0.25×[(2.8+4.4)÷1.2]3.7×9.16+6.3×9.16
[32-(1.95-1.95)]÷1.65.7×10.1.

解:(1)0.25×[(2.8+4.4)÷1.2],
=0.25×[7.2÷1.2],
=0.25×6,
=1.5;

(2)3.7×9.16+6.3×9.16,
=(3.7+6.3)×9.16,
=10×9.16,
=91.6;

(3)[32-(1.95-1.95)]÷1.6,
=[32-0]÷1.6,
=32÷1.6,
=20;

(4)5.7×10.1,
=5.7×(10+0.1),
=5.7×10+5.7×0.1,
=57+0.57,
=57.57.
分析:(1)(3)先算小括号内的,再算中括号内的,最后算括号外的;
(2)运用乘法分配律简算;
(4)把10.1看作10+0.1,然后运用乘法分配律简算.
点评:此题考查了小数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算律简便计算.
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