题目内容
计算.(怎样算简便就怎样算)
1.47÷(2-1.02)+0.15 | 3.9×3.6+3.9×6.4 |
25.2÷4.5+3.25×1.4 | . |
解:①1.47÷(2-1.02)+0.15,
=1.47÷0.98+0.15,
=1.5+0.15,
=1.65;
②3.9×3.6+3.9×6.4,
=3.9×(3.6+6.4),
=3.9×10,
=39;
③25.2÷4.5+3.25×1.4,
=5.6+4.55,
=10.15;
④÷[(-)×],
=÷[×],
=÷,
=×,
=7.
分析:①1.47÷(2-1.02)+0.15,先算小括号里的2-1.02再算除和加;
②3.9×3.6+3.9×6.4利用乘法的分配律变成3.9×(3.6+6.4)计算简便;
③25.2÷4.5+3.25×1.4把25.2÷4.5和3.25×1.4同时计算,再算加;
④先算先括号里-,再算中括号里的乘,最后算除.
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.
=1.47÷0.98+0.15,
=1.5+0.15,
=1.65;
②3.9×3.6+3.9×6.4,
=3.9×(3.6+6.4),
=3.9×10,
=39;
③25.2÷4.5+3.25×1.4,
=5.6+4.55,
=10.15;
④÷[(-)×],
=÷[×],
=÷,
=×,
=7.
分析:①1.47÷(2-1.02)+0.15,先算小括号里的2-1.02再算除和加;
②3.9×3.6+3.9×6.4利用乘法的分配律变成3.9×(3.6+6.4)计算简便;
③25.2÷4.5+3.25×1.4把25.2÷4.5和3.25×1.4同时计算,再算加;
④先算先括号里-,再算中括号里的乘,最后算除.
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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