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下面各题怎样简便就怎样计算(2)36.26-4.78+3.74(3)7.34+7.57+12.66+6.43 (4)78.65-23.12-14.88.

编辑:chaxungu时间:2026-04-26 09:11:01分类:小学数学题库

下面各题怎样简便就怎样计算
(1)12.64-(3.96+4.64)
(2)36.26-4.78+3.74
(3)7.34+7.57+12.66+6.43    
(4)78.65-23.12-14.88.解:(1)12.64-(3.96+4.64),
=12.64-3.96-4.64,
=12.64-4.64-3.96,
=8-3.96,
=4.04;

(2)36.26-4.78+3.74,
=36.26+3.74-4.78,
=40-4.78,
=35.22;

(3)7.34+7.57+12.66+6.43,
=(7.34+12.66)+(7.57+6.43),
=20+14,
=34;

(4)78.65-23.12-14.88,
=78.65-(23.12+14.88),
=78.65-38,
=40.65.
分析:(1)运用减法的性质以及加法交换律简算;
(2)运用加法交换律简算;
(3)运用加法交换律、结合律简算;
(3)运用减法的性质简算.
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.