题目内容
请写出过程 ①99×99+99 | ②10×0.1×100 | ③8÷8÷0.125 | ④37×39-29×37 |
⑤1.8÷2.7÷0.6×2.7 | ⑥47×99 | ⑦0.5+[÷(0.15+)] | ⑧[(+2.1)×]÷0.9. |
解:①99×99+99,
=99×(99+1),
=99×100,
=9900;
②10×0.1×100,
=1×100,
=100;
③8÷8÷0.125,
=8÷(8×0.125),
=8÷1,
=8;
④37×39-29×37,
=37×(39-29),
=37×10,
=370;
⑤1.8÷2.7÷0.6×2.7,
=1.8÷0.6,
=3;
⑥47×99,
=47×(100-1),
=47×100-47,
=4700-47,
=4653;
⑦0.5+[÷(0.15+)],
=0.5+[÷(0.15+0.45)],
=0.5+(÷),
=+,
=,
=;
⑧[(+2.1)×]÷0.9,
=(×+2.1×),
=(+)×,
=×+,
=+,
=,
=1.
分析:①④⑥利用乘法分配律简算;
③利用除法的性质简便运算;
其余题目按照运算顺序解答即可.
点评:灵活应用乘法分配律及其逆运算来解题,使计算更简单.
=99×(99+1),
=99×100,
=9900;
②10×0.1×100,
=1×100,
=100;
③8÷8÷0.125,
=8÷(8×0.125),
=8÷1,
=8;
④37×39-29×37,
=37×(39-29),
=37×10,
=370;
⑤1.8÷2.7÷0.6×2.7,
=1.8÷0.6,
=3;
⑥47×99,
=47×(100-1),
=47×100-47,
=4700-47,
=4653;
⑦0.5+[÷(0.15+)],
=0.5+[÷(0.15+0.45)],
=0.5+(÷),
=+,
=,
=;
⑧[(+2.1)×]÷0.9,
=(×+2.1×),
=(+)×,
=×+,
=+,
=,
=1.
分析:①④⑥利用乘法分配律简算;
③利用除法的性质简便运算;
其余题目按照运算顺序解答即可.
点评:灵活应用乘法分配律及其逆运算来解题,使计算更简单.
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