题目内容
1.45+0.38+9.55 | 8.65-(0.76+4.65) | 28.8-2.6-7.4 | 0.79-0.54+0.21-0.46. |
分析:(1)运用加法交换律与结合律简算;
(2)(4)运用减法的性质以及加法交换律与结合律简算;
(3)运用减法的性质简算.
(2)(4)运用减法的性质以及加法交换律与结合律简算;
(3)运用减法的性质简算.
解答:解:(1)1.45+0.38+9.55,
=(1.45+9.55)+0.38,
=11+0.38,
=11.38;
(2)8.65-(0.76+4.65),
=8.65-0.76-4.65,
=(8.65-4.65)-0.76,
=4-0.76,
=3.24;
(3)28.8-2.6-7.4,
=28.8-(2.6+7.4),
=28.8-10,
=18.8;
(4)0.79-0.54+0.21-0.46,
=(0.79+0.21)-(0.54+0.46),
=1-1,
=0.
=(1.45+9.55)+0.38,
=11+0.38,
=11.38;
(2)8.65-(0.76+4.65),
=8.65-0.76-4.65,
=(8.65-4.65)-0.76,
=4-0.76,
=3.24;
(3)28.8-2.6-7.4,
=28.8-(2.6+7.4),
=28.8-10,
=18.8;
(4)0.79-0.54+0.21-0.46,
=(0.79+0.21)-(0.54+0.46),
=1-1,
=0.
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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