题目内容
下面各题怎样简便就怎样算. 472+66+134 | 324+75+46+25+54 |
283+36+64+17 | 15+57+185 |
125+75+26+74 | 98+(24+102) |
解:(1)472+66+134,
=472+(66+134),
=472+200,
=672;
(2)324+75+46+25+54,
=324+(75+25)+(54+46),
=324+100+100,
=524;
(3)283+36+64+17,
=(283+17)+(36+64),
=300+100,
=400;
(4)15+57+185,
=(15+185)+57,
=200+57,
=257;
(5)125+75+26+74,
=(125+75)+(26+74),
=200+100,
=300;
(6)98+(24+102),
=98+24+102,
=(98+102)+24,
=200+24,
=224.
分析:(1)(4)(6)运用加法交换律简算;
(2)(3)运用加法交换律与结合律简算;
(5)运用加法结合律简算.
点评:完成此题,应注意分析式中数据,运用所学的运算定律或性质,进行简算.
=472+(66+134),
=472+200,
=672;
(2)324+75+46+25+54,
=324+(75+25)+(54+46),
=324+100+100,
=524;
(3)283+36+64+17,
=(283+17)+(36+64),
=300+100,
=400;
(4)15+57+185,
=(15+185)+57,
=200+57,
=257;
(5)125+75+26+74,
=(125+75)+(26+74),
=200+100,
=300;
(6)98+(24+102),
=98+24+102,
=(98+102)+24,
=200+24,
=224.
分析:(1)(4)(6)运用加法交换律简算;
(2)(3)运用加法交换律与结合律简算;
(5)运用加法结合律简算.
点评:完成此题,应注意分析式中数据,运用所学的运算定律或性质,进行简算.
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